Question

A boy weighing 40 kg makes a high jump of 4m. (g=10m/s^2)
i) What is his kinetic energy at the middle of the high jump?
ii) What is his potential energy at the highest point?
(Answer: 800J, 1600J)
Show the working out

Answer 1

Answer:

Solution

Explanation:

Mass of the boy, m=40 kg

Height, h=1.5 m

At highest point,

velocity, v=0 m/s

(i) Kinetic energy at the highest point, KE=  

2

1

​

mv  

2

 

KE=  

2

1

​

×40×(0)  

2

 

KE=0 J

(ii) Potential energy at the highest point, U=mgh  (where g=acceleration due to gravity

U=40×9.8×1.5

U=588 J