Question

A ball strikes the floor vertically downward with a
speed 5 m/s and rebounds with the same speed.
The magnitude of its change in velocity will be
(1) Zero
(2) 5 m/s
(3) 10 m/s
(4) 40 m/s
Please explain step by step not directly ​

Answer 1

Answer:

The answer will be zero

Explanation:

the ball strikes with the velocity of 5 m/s and returns with the same velocity.

Since the ball is returing, the velocity will be -5m/s

Therefore,

5m/s-5m/s=0

Answer 2

${\underline{\sf{Given}}}$

• A ball Strikes the floor vertically downward by 5m/s.
• And ball rebounds with same Speed.

${\underline{\sf{To\:Find}}}$

The magnitude of its change in velocity.

${\underline{\sf{Solution}}}$

Let the velocity at instance when it strikes the ground be V.

Velocity when it strikes the ground = V

According to the Question :

Ball rebounds with same Speed.

Thus , Velocity when it rebounds = -V

Change in velocity

${\purple{\boxed{\large{\bold{\triangle\:V=V_{f}-V_{i}}}}}}$

= -V -(V) = -2V

Note :

Here , negative sign implies that it is in opposite directions of velocity we've take the magnitude.

$\rule{200}2$

Magnitude of change in velocity

= |∆V| = |-2v| = 2v

= 10m/s

Therefore,

Correct option is 3) 10m/s