Question

1: A hammer of mass 1 kg falls freely from a height of 2m. Calculate..
(a) the velocity with which it
hits the ground and

(b) the kinetic energy of the
hammer just before it
touches the ground.



2: A bullet of mass 20 g moving with a velocity of 20 m/s is brought to rest by a wooden plank. Calculate the work done on the bullet before it comes to rest.


❌ PLEASE don't SpaM❌​

Answer 1

Explanation:

1. Velocity of hammer, v = 6.26 m/s

2. Kinetic energy, E = 19.59 J

Explanation:

It is given that,

Mass of the hammer, m = 1 kg

Height, h = 2 m

(1) Let v is the velocity of hammer. It can be calculated using conservation of energy as :

v=\sqrt{2gh}v=

2gh

v=\sqrt{2\times 9.8\times 2}v=

2×9.8×2

v = 6.26 m/s

(2) Let E is the kinetic energy of the hammer just before it touches the ground. It is given by :

E=\dfrac{1}{2}mv^2E=

2

1

mv

2

E=\dfrac{1}{2}\times 1\times (6.26)^2E=

2

1

×1×(6.26)

2

E = 19.59 J