Question

13. 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.​

Answer 1

Answer:

mass, m = 20g (0.02kg)

initial velocity, u = 75m/s

final velocity = 0m/s

distance, s = 5cm or 0.05m

Using, v

2

= u

2

+ 2as

0 = 75

2

+ 2a(0.05)

a = 562.5m/s

2

$$ Force = mass \times acceleration $$

$$ = 0.02 \times 562.5 $$

= 11.25N

Explanation:

as you can put 20 ms removing 75 ms

Answer 2

$\small\underline\purple{Given:-}$

mass, m = 20g (0.02kg)

initial velocity, u = 75m/s

final velocity = 0m/s

distance, s = 5cm or 0.05m

$\small\underline\purple{Using Formula:-}$

${v}^{2} + {u}^{2} = 2as$

$0 = {75}^{2} + 2a(0.5)$

$a = 562.5 \frac{m}{s} ^{2}$

$\small\underline\purple{Now:-}$

Force = mass \times acceleration

= 0.02 \times 562.5

= 11.25N

$\sf\small\underline\purple{Note:-}$

The mass and distance must be converted in to SI unit of system. Then you would get answer in newtons.