Question

A stone of mass 200g is thrown vertically upwards with a velocity of 60 m/s. What is the potential energy and kinetic energy after 5 seconds.​
please answer step by step.

Answer 1

Answer:

K.E=

2

1

×m×v

2

K.E=0.5×0.2×20×20=40J

As it has 40 J at initial point as total energy, at some point X,P.E is maximum.

Total energy=P.E+K.E

40=P.E+K.E

As energy is conserved, total energy at point X also must be 40 J. For P.E to be maximum K.E must be zero.

Hence P.E=40J

We can come to the conclusion that it will have the maximum value at maximum height.

Answer 2

Explanation:

Since the ball is thrown upward so as per equation “v=u+at” by keeping value of v=0 ,u=30 and a=g(acceleration due to earth' gravity) we get to know that in approximately 3s (takeg=10m/s^2) the ball will stop and start moving downwards so then after 2 seconds its velocity 'v' will be v=u+at here u=0 so v will be 20m/s.Hence kinetic energy will be after 5s of throwing ball upwards 0.5*m*v^2 so it will be 0.2*20*20*0.5=40 joules(by taking g=10m/s^2)