Question

a ball is dropped from a building of height 45m. Simultaneously another ball is thrown up wth a speed 40m/s. Calculate the relative speed of the balls as a function of time.

Answer 1

Answer:

The relative speed of the balls as a function of time is 40 m/s.

Explanation:

Given : A ball is dropped from a building of height 45 m. Simultaneously another ball is thrown up with a speed 40 m/s.

To find : Calculate the relative speed of the balls as a function of time ?

Solution :

According to question,

When ball is dropped from the building,

The initial velocity is $u_1=0\ m/s$

The velocity of the ball after time t,

$v_1=u_1-gt$

$v_1=-gt$ ...(1)

When another ball which is thrown upward,

The initial velocity is $u_2=40\ m/s$

The velocity of the ball after time t,

$v_2=u_2-gt$

$v_2=40-gt$ ...(2)

Relative velocity of one ball w.r.t another ball is

$v_{12}=v_1-v_2$

Substitute from (1) and (2),

$v_{12}=-gt+40+gt$

$v_{12}=40\ m/s$

Therefore, The relative speed of the balls as a function of time is 40 m/s.

Answer 2

Answer: 40m/s

Explanation: