A hockey puck with mass 0.160 kg is at rest at the origin (x=0) on the horizontal, frictionless surface of the rink. At time t = 0 a player applies a force of 0.250 N to the puck, parallel to the x-axis; he continues to apply this force until t = 2.00s.

What is the position of the puck at t = 2.00s ?
In this case what is the speed of the puck?
If the same force is again applied at t = 5.00s , what is the position of the puck at t = 7.00s ?
In this case what is the speed of the puck?

a) , b) , c) , d)

Explanation:

a) Position of the puck:

The acceleration experimented by the puck is:

As the force remains constant during its time of application, accelaration is also constant. Position at given time is the following:

b) Speed of the puck:

The speed of the puck is computed as follows:

c) The absence of external force and the fact that ground is frictionless lead to the conclusion that hockey puck moves out at constant speed from 2 s. to 5 s. Then, the initial speed is:

Likewise, the initial speed is .

The new application of the same force means the return of a accelerated movement. Then:

d) The final speed of the puck is:

false br

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.