Question

. A body of mass 5 kg is moving with a uniform velocity of 10 m/s. It is acted upon by a
force of 20 N. What will be its velocity after 1 s?​

Answer 1

Answer:-

v = 14 m/s

Given :-

$m = 5 kg\\ u = 10 m/s \\ t= 1s \\ F = 20 N$

To find :-

It's velocity after 1s.

Solution:-

Let the velocity after 1s be v.

Acceleration is given by formula :-

→$a = \dfrac{v-u}{t}$

→$a = \dfrac{v-10}{1}$

→$a = v -10$

Now,

The magnitude of force is given by :-

• Using Newton 2nd law of motion.

→$F = m a$

• put the value of a .

→$F = m (v -10)$

→$20 = 5 (v-10)$

→$20 = 5v -50$

→$5v = 20 + 50$

→$5v = 70$

→$v = \dfrac{70}{5}$

→$v = 14 m/s$

hence,

The Velocity after 1s is 14 m/s.

Answer 2

Answer:

Explanation:

Given :-

Mass of the body, m = 5 kg

Initial speed of a body, u = 10 m/s

Time taken by the body, t = 1 seconds

Force exert on the body, F = 20 Newton

To Find :-

Final speed, v = ??

Formula to be used :-

Force = mass × acceleration

1st equation of motion i.e v = u+ at

Solution :-

Putting all the values, we get

Force = Mass × Acceleration

⇒ Acceleration =Force / mass

⇒ Acceleration = 20N / 5kg

⇒ Acceleration = 4 m/s².

Putting Acceleration value in v = u+ at, we get

⇒ v = u+ at

⇒ v = 10+(4)(1)

⇒ v = 14 m/s

Hence, the velocity after 1 second is 14 m/s.