A gymnast of mass 65 kg bounces vertically on a trampoline so that she approaches and leaves the trampoline with a speed of 10 m/s and
contact time of 0.9 s. Calculate (1) her change of momentum (ii) the
average resultant force exerted on her while in contact with the
trampoline​

Change in momentum:

Average resultant force: approximately .

Explanation:

Consider an object of mass travelling at velocity . The momentum of this object would be .

Momentum is a vector. The direction of an object's momentum is the same as the direction of its velocity.

Initial velocity of this gymnast: . This value is negative because the gymnast was initially travelling downwards.

Hence, the initial momentum of this gymnast would be:

.

Velocity of this gymnast after leaving the trampoline: .

Hence, the momentum of this gymnast when leaving the trampoline would be:

.

Change in momentum:

.

By Newton's Second Law of motion, if the momentum of an object changed by over time , the average net force on that object would be:

.

For this gymnast:

.

u can delete ur account.

1. go on google and write

2 open this and click on your profile pic and if your profile is not appearing, then u have to log in.

3. when u click on your profile pic, there appears four options on the top.

4. click on the 1st option and scroll down and go at the bottom.

5. click on edit profile.

6. there appears a option 'prefernces' and at that option at the right side , 'edit' is written.

7. click on the edit option.

8. there is a option " i want to delete my account" and click on that.

hope this u

and ur welcm

: )