A body of mass 2 kg starts from rest and moves with uniform acceleration. It acquires a velocity 20 m s-1 in 4 s. The power exerted on the body in 2 s in watts is

Question

A body of mass 2 kg starts from rest and moves with uniform acceleration. It acquires a velocity 20 m s-1 in 4 s. The power exerted on the body in 2 s in watts is (A) 50 (B) 100 (C) 150 (D) 200

Tardigrade Admin · Accepted Answer

Let a body moves with uniform acceleration a. From

v = u + a t

Here,

u = 0, v = 20 m s^{- 1}, t = 4 s

∴ a = \frac{υ - u}{t} = \frac{20 - 0}{4} = 5 m

Force exerted on the body,

F = m \times a = (2 k g) (5 m s^{- 2}) = 10 N

Velocity acquired by the body in

2 s

is

υ = (5 m s^{- 2}) (2 s) = 10 m s^{- 1}

The power exerted on the body in

2 s

is

P = F υ = (10 N) (10 m) = 100 W

Q. A body of mass $2 k g$ starts from rest and moves with uniform acceleration. It acquires a velocity $20 m s^{- 1}$ in $4 s$ . The power exerted on the body in $2 s$ in watts is

$50$

$100$

$150$

$200$

Q. A body of mass 2kg starts from rest and moves with uniform acceleration. It acquires a velocity 20ms−1 in 4s. The power exerted on the body in 2s in watts is

50

100

150

200

Let a body moves with uniform acceleration a. From v=u+at Here, u=0,v=20ms−1,t=4s ∴a=tυ−u​=420−0​=5m Force exerted on the body, F=m×a=(2kg)(5ms−2)=10N Velocity acquired by the body in 2s is υ=(5ms−2)(2s)=10ms−1 The power exerted on the body in 2s is P=Fυ=(10N)(10m)=100W

Q. A body of mass $2 k g$ starts from rest and moves with uniform acceleration. It acquires a velocity $20 m s^{- 1}$ in $4 s$ . The power exerted on the body in $2 s$ in watts is

$50$

$100$

$150$

$200$