Questions about Chapter 2: Motion along a straight line.

Question 1:

The motion of a particle traveling along the x-axis is described by the equation

x = 20 + 4 *  t2

where x is in m and t in s.

(a)  Find the average velocity of the particle in the time interval from t = 2 s to t = 5 s
(b)  Find the instantaneous velocity of the particle at t = 2 s.

ANS:    (a)    28 m/s      (b)    16 m/s

Question 2:

A ball is thrown vertically upward and reaches a maximum height of 35 m.  Upon descending to the ground it rebounds with half its initial velocity.  Find the height to which it climbs after rebounding ?

ANS:     8.75 m.

Question 3:

A stone is thrown vertically upward with a velocity of 9.8 m/s from the top of a building whose height is 73.5 m.  How long will the stone take to reach the ground ?

ANS:    5 s.

Question 4:

A stone is dropped from the top of a very tall building.  One second later another    stone is thrown vertically downward with a speed of 12 m/s.  How far below the top of the building will the second stone overtake the first ?

ANS:   51 m.

Question 5:

A car is initially travelling in a straight line and at a speed of 100 km/hr.  The driver accelerates  the car at a rate of 15 m/s2 for 7 s.  How far does the car travel while it is being accelerated ?

ANS:    562 m.

Question 6:

A ball is thrown vertically upward with an initial speed of 8.00 m/s from a height of 30.0 m above the ground.

(a)  When does the ball strike the ground ?

(b)  Calculate the velocity of the ball just before it strikes the ground.

Question 7:

A stone is dropped from a bridge that is 940 m above the water.  Another stone   is thrown vertically downward form this bridge 1.0 s after the first stone is dropped.  Both stones strike the water at the same time.

(a) How long will it take the first stone to strike the water ?

(b) What was the initial speed of the second stone?