Classical Mechanics Answers

The periodic time of a body executing simple harmonic motion is 4s. After how many intervals from time t=0, its displacement will be half of its amplitude?
1 : 1/2 s
2 : 1/3 s
3 : 1/4 s
4 : 1/6 s

When a 2 kg body is suspended by a spring, the spring is stretched. If the body is pulled down slightly and released, it oscillates up and down. What force is applied on the body by the spring when it passes through the mean position?
1 : Force equal to the gravity
2 : Force equal to the pull
3 : Conservative force
4 : Force equal to the weight of the body

A (field) hockey player is running north at a speed of 8 m⋅s−18 \text{ m}\cdot\text{s}^{-1}8 m⋅s−1. A ball is coming directly towards her from the north at a speed of 18 m⋅s−118\text{ m}\cdot\text{s}^{-1}18 m⋅s−1. She swings her stick forward, directly north, at a speed of 6 m⋅s−16\text{ m}\cdot\text{s}^{-1}6 m⋅s−1 measured in her own frame of reference. What is the speed of the ball with respect to the hockey stick?

a boy standing in the elivator which moving down with acceleration of "a" . he tossed the coin . all of sudden the string is of elevator is broken down and elevator under free fall motion . the coin will reach in his hand in time

a 25 cm. thick block of ice floating on fresh water can support an 80 kg man standing on it, what is the smallest area of the ice block? (sp gr. of ice=0.917)

A body is called as rigid body if?

A. distance between points remains variable
B. change in volume is negligible
C. change in volume is significant
D. all of these

If the forces between interacting bodies are equal, opposite and collinear, how is it that bodies are able to be accelerated if it these forces cancel each other out?
A. None
B. The masses of the two bodies could be different and this difference causes acceleration.
C. The two forces are acting on different bodies; to analyze acceleration, we need to look at the forces acting only on one body.
D. In real life, the forces are not exactly equal and this difference causes acceleration.

In mechanics, we can apply a force along any point on the line of action of the force without changing the effect of the force on the body. This is only permissible if:

A. We consider the body to deformable or non-rigid
B. We consider the body to a rigid body
C. The force is not too large
D. None