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प्रश्न
Read the statement below carefully and state, with reason and example, if it is true or false:
A particle in one-dimensional motion with positive value of acceleration must be speeding up.
विकल्प
True
False
उत्तर
This statement is False.
Explanation:
A particle in one-dimensional motion with a positive value of acceleration is not necessarily speeding up. The particle will speed up only if its velocity and acceleration are in the same direction. If the velocity and acceleration are in opposite directions (for example, if the particle is moving in the negative direction while the acceleration is positive), the particle is actually slowing down.
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संबंधित प्रश्न
Read the statement below carefully and state, with reason and example, if it is true or false:
A particle in one-dimensional motion with constant speed must have zero acceleration.
Suggest a suitable physical situation for the following graph:
The given figure gives a speed-time graph of a particle in motion along a constant direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude? In which interval is the average speed greatest? Choosing the positive direction as the constant direction of motion, give the signs of v and a in the three intervals. What are the accelerations at the points A, B, C and D?
If a particle is accelerating, it is either speeding up or speeding down. Do you agree with this statement?
Give example where the velocity of a particle is zero but its acceleration is not zero.
Give example where the velocity is opposite in direction to the acceleration.
In figure shows the x coordinate of a particle as a function of time. Find the sings of vx and ax at t = t1, t = t2 and t = t3.
An object having a velocity 4.0 m/s is accelerated at the rate of 1.2 m/s2 for 5.0 s. Find the distance travelled during the period of acceleration.
A graph of x versus t is shown in figure. Choose correct alternatives from below.
- The particle was released from rest at t = 0.
- At B, the acceleration a > 0.
- At C, the velocity and the acceleration vanish.
- Average velocity for the motion between A and D is positive.
- The speed at D exceeds that at E.
An object falling through a fluid is observed to have acceleration given by a = g – bv where g = gravitational acceleration and b is constant. After a long time of release, it is observed to fall with constant speed. What must be the value of constant speed?
