Question

1. A ball of mass 2kg is thrown up with the speed of 10m/s.Find the kinetic energy of the ball at the time of throwing?
2. An object with 100N is raised to height of 15m.Find the potential energy of the object at that height?[Given g= 10m/s2].
3. Calculate the Kinetic energy of the jogger of mass 75Kg travelling at speed of 2.5 m/s?
4. If a body of mass 2 kg is moving with velocity of 20m/s. Calculate its Kinetic energy? What will happen if the mass of body is doubled? Will the Kinetic energy remain same?
5. What is the energy conversion taking place in the following cases
a) Burning of Crackers
b) Lighting of torch

Answer 1

Answer:

1.100j 2.15000j 3.93.75j 4.20j

Explanation:

1.kinetic energy=1/2mv2

=1/2*2*10*10

=100joule

2.P.E=mgh

=100*10*15

=15000j

3.K.E=1/2*75*2.5

=93.75j

4.K.E=1/2*2*20

=20j

if mass is double then joule will also double.

so it will 40joule

No,kinetic energy will not same.

5.a)heat

b)chemical