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Q1. In the formula v = (2πr)/t, t represents:
In the formula v = (2πr)/t, 2πr is the circumference of the circular path (the distance covered in one complete round). Therefore, t represents the time taken to complete one full round, which is also called the time period.
Q2. The stone tied to a thread shows that circular motion involves:
When a stone tied to a thread is whirled around, its speed may remain constant but its direction keeps changing continuously. This change in direction is what makes the motion circular. The thread provides the force that causes this continuous change in direction.
Q3. Motion can be classified as:
Motion can be broadly classified into two main types based on how speed changes: uniform motion (constant speed) and non-uniform motion (changing speed). Circular, rectilinear, and oscillatory are types based on the path, not the nature of speed.
Q4. The circumference of a circle of radius r is:
The circumference is the total distance around a circle. For a circle of radius r, the circumference is given by the formula C = 2πr. This is the distance covered by an object in one complete round of circular motion.
Q5. The motion of a cyclist on a circular track at constant speed is an example of:
When a cyclist moves on a circular track with constant speed, the speed remains the same but the direction changes continuously. This is the definition of uniform circular motion. Even though speed is constant, the motion is accelerated because velocity changes due to change in direction.
Q6. The third equation of motion connects velocity, acceleration and:
The third equation of motion is v² = u² + 2as. It relates final velocity (v), initial velocity (u), acceleration (a), and displacement or distance (s). It does not involve time, which is why it is useful when time is not given in the problem.
Q7. Distance–time graph for uniform motion is a:
In uniform motion, the object covers equal distances in equal intervals of time. When plotted on a distance-time graph, this gives a straight line inclined to the time axis. The slope of this line gives the constant speed of the object.
Q8. In uniform circular motion, acceleration acts:
In uniform circular motion, the acceleration is called centripetal acceleration, which always acts towards the centre of the circle. This acceleration is responsible for changing the direction of the velocity without changing its magnitude.
Q9. On a circular track with constant speed, the athlete’s velocity is not constant because:
Velocity is a vector quantity that includes both speed and direction. Even though the athlete’s speed is constant, his direction is continuously changing as he moves along the circular track. This change in direction means his velocity is not constant.
Q10. What happens to the piece of stone tied to a thread when it is released from circular motion?
When the stone is released from circular motion, the tension in the thread (which provided the centripetal force) is removed. The stone then moves in a straight line in the direction it was moving at the instant of release, which is along the tangent to the circle at that point.
Q11. Once released from circular motion, the stone moves in a straight line due to:
Inertia is the tendency of an object to resist any change in its state of motion. The stone continues to move in the direction it was moving at the moment of release because of its inertia of direction. It does not require any force to keep moving in a straight line.
Q12. Uniform circular motion proves that acceleration can exist even when:
Uniform circular motion is a classic example where acceleration exists even though speed is constant. The acceleration is due to the continuous change in direction. This proves that acceleration is the rate of change of velocity, not just speed, and can occur even when speed is constant.
Q13. In the equation s = ut + ½at², the letter ‘s’ stands for:
In the second equation of motion, s = ut + ½at², the letter s represents the distance travelled by the object. In some textbooks, it may also be referred to as displacement when motion is in a straight line without change in direction.
Q14. Which of the following is NOT an example of uniform circular motion?
Uniform circular motion requires a circular path. A train moving on a straight track moves in a straight line, not a circle. Even though its speed is constant, it is an example of uniform linear motion, not uniform circular motion.
Q15. Velocity differs from speed because velocity includes:
Speed is a scalar quantity that only tells us how fast an object is moving. Velocity is a vector quantity that includes both the speed and the direction of motion. This is the fundamental difference between the two quantities.
Q16. When an object’s velocity changes, the object is said to be:
Acceleration is defined as the rate of change of velocity. So whenever there is a change in velocity, whether it is a change in speed, direction, or both, the object is said to be accelerating.
Q17. What is the motion called when an object moves in a circular path with uniform speed?
When an object moves along a circular path with a constant speed, the motion is called uniform circular motion. The word “uniform” refers to the constant speed, while “circular” refers to the circular path.
Q18. What is the nature of the path in uniform circular motion?
As the name suggests, uniform circular motion involves motion along a circular path. The path is a circle, meaning the object remains at a fixed distance from a central point throughout its motion.
Q19. As the number of sides of a track increases indefinitely, its shape approaches that of a:
A polygon with many sides approximates a circle as the number of sides increases. When a track has an infinite number of very small sides, it becomes a smooth circular path. This is the basis of understanding circular motion as a limiting case of polygonal motion.
Q20. Motion along a circular path at constant speed is:
Even though the speed is constant, the direction changes continuously. Since velocity includes direction, the velocity is changing. Any change in velocity means the object is accelerating. So circular motion at constant speed is accelerated motion.
Q21. When an athlete gives a hammer a circular motion before throwing, the hammer just before release is in:
When the athlete rotates the hammer, it moves in a circular path. If the speed is constant during the rotation, the hammer is in uniform circular motion just before it is released. After release, it will move in a straight line.
Q22. The equations of motion are valid only when:
The three equations of motion (v = u + at, s = ut + ½at², v² = u² + 2as) are derived assuming that the acceleration is constant or uniform. They cannot be applied when acceleration is changing with time.
Q23. Which situation involves change in direction?
A U-turn involves a change in the direction of motion. Even if the speed is constant, the direction changes, which means the velocity changes. This is a situation involving change in direction.
Q24. What is the key requirement for uniform circular motion?
The key requirement for uniform circular motion is that the object must move with constant speed along a circular path. The speed should not increase or decrease. The acceleration exists only to change the direction, not the speed.
Q25. A change in direction of motion indicates:
Velocity is a vector quantity that includes both speed and direction. Therefore, any change in direction, even if speed remains constant, results in a change in velocity. This is why circular motion at constant speed is still considered accelerated motion.
Q26. In the equation v = u + at, the letter ‘u’ stands for:
In the first equation of motion, v = u + at, the letter u represents the initial velocity of the object at the start of the time interval. v represents the final velocity after time t.
Q27. Can an object accelerate without changing its speed?
Yes, an object can accelerate without changing its speed by changing its direction. Uniform circular motion is the perfect example. The speed remains constant, but because the direction changes continuously, the velocity changes, which means there is acceleration.
Q28. This mock test mainly deals with:
The questions in this test cover various aspects of motion including types (uniform, non-uniform, circular), concepts like speed, velocity, acceleration, displacement, equations of motion, and graphs. It deals broadly with the description of motion in physics.
Q29. In uniform circular motion, the magnitude of velocity is:
In uniform circular motion, the speed is constant, and the magnitude of velocity is the same as speed. So the magnitude of velocity remains constant throughout the motion. Only the direction of velocity changes.
Q30. An athlete running along a rectangular track changes his direction of motion how many times in one round?
A rectangle has four corners. At each corner, the athlete must change direction to continue along the next side of the track. Therefore, in one complete round of a rectangular track, the athlete changes direction four times.
Q31. The motion of an object is uniform if its:
Uniform motion means the object covers equal distances in equal intervals of time, which means its speed is constant. However, for uniform motion along a straight line, the velocity is also constant. But among the options, speed being constant is the defining feature.
Q32. Why does the stone move in a straight line when released?
This is due to Newton’s first law of motion, also called the law of inertia. When the thread is released, the centripetal force is removed. The stone continues in a straight line in the direction of its velocity at that instant, which is along the tangent to the circle.
Q33. The hammer thrower rotates before release to:
The hammer thrower rotates the hammer in a circular motion to give it a high speed before release. When released, the hammer moves in a straight line tangent to the circle with this high speed, allowing it to travel a large distance.
Q34. When an object is in uniform circular motion, it is:
In uniform circular motion, the object is always accelerating because its direction keeps changing. This acceleration is directed towards the centre of the circle (centripetal acceleration). Even though the speed is constant, the acceleration exists due to the change in direction.
Q35. When an object moves with constant speed along a circular path, what changes?
When an object moves along a circular path, even at constant speed, the direction of motion keeps changing at every point. Since velocity includes direction, the velocity changes continuously, even though the speed (magnitude of velocity) remains constant.
Q36. The motion of the Moon around the Earth is an example of:
The Moon moves around the Earth in an almost circular orbit with nearly constant speed. Therefore, its motion is approximately uniform circular motion. The gravitational force of the Earth provides the necessary centripetal force.
Q37. The word ‘uniform’ in uniform circular motion refers to:
In uniform circular motion, the word “uniform” refers to the constant speed of the object. The speed does not change, even though the direction changes continuously. The radius is also constant for a circle, but that is not what “uniform” refers to.
Q38. Speed is defined as:
Speed is the rate at which an object covers distance. It is calculated as the total distance traveled divided by the total time taken. It is a scalar quantity and does not involve direction.
Q39. The motion of objects can be shown through:
The motion of objects can be represented using graphs such as distance-time graphs, velocity-time graphs, and acceleration-time graphs. These graphs provide a visual understanding of how quantities like distance, velocity, and acceleration change with time.
Q40. What remains constant in uniform circular motion?
In uniform circular motion, the speed of the object remains constant. However, the velocity changes because its direction changes continuously. The acceleration also changes direction but has a constant magnitude towards the centre.
Q41. The motion of an object is non-uniform if its:
Non-uniform motion means the object does not cover equal distances in equal intervals of time. This results in a changing velocity, which could mean a change in speed, direction, or both. Uniform motion, on the other hand, has constant velocity.
Q42. The formula for the speed of an object in uniform circular motion is v = (2πr)/t, where r is:
In the formula v = (2πr)/t, r represents the radius of the circular path. The term 2πr is the circumference of the circle. The formula gives the speed of the object by dividing the total distance of one round (circumference) by the time taken.
Q43. The slope of a distance–time graph gives:
The slope of a distance-time graph is calculated as change in distance divided by change in time, which is the definition of speed. A steeper slope means higher speed, while a horizontal line means zero speed (object at rest).
Q44. Acceleration is defined as:
Acceleration is the rate at which velocity changes with time. It is a vector quantity. Since velocity includes both speed and direction, acceleration can result from a change in speed, direction, or both.
Q45. In uniform circular motion, the change occurs in the _____ of velocity.
In uniform circular motion, the magnitude of velocity (speed) remains constant, but the direction of velocity changes continuously. So the change occurs specifically in the direction of velocity, not in its magnitude.
Q46. Velocity is defined as:
Velocity is a vector quantity that describes how fast an object is moving and in which direction. It is the speed of the object along with its direction of motion. This distinguishes it from speed, which only gives the magnitude.
Q47. The change in velocity of an object can be due to a change in:
Velocity is a vector quantity made up of speed (magnitude) and direction. Therefore, a change in velocity can occur if the speed changes, if the direction changes, or if both change simultaneously.
Q48. Distance and displacement are:
Distance and displacement are different concepts. Distance is the total length of the actual path traveled and is a scalar quantity. Displacement is the shortest straight-line distance between the starting and ending points and is a vector quantity. They are equal only when the motion is in a straight line without changing direction.
Q49. The equations of motion are used to describe motion with:
The three equations of motion (v = u + at, s = ut + ½at², v² = u² + 2as) are specifically derived for situations where acceleration is constant or uniform. They cannot be applied when acceleration is changing with time.
Q50. Motion can be described in terms of:
Motion can be described using either distance (scalar) or displacement (vector), depending on whether we are interested in the total path length or the change in position. Both are valid ways to describe motion, and the choice depends on the information needed.