A body of mass 10 kg is acted upon by a force given by equation F=(3 t2-30) newtons. The initial velocity of the body is 10 m / s. The velocity of the body after 5 s is

Question

A body of mass 10 kg is acted upon by a force given by equation F=(3 t2-30) newtons. The initial velocity of the body is 10 m / s. The velocity of the body after 5 s is (A) 4.5 m / s (B) 6 m / s (C) 7.5 m / s (D) 5 m / s

Tardigrade Admin · Accepted Answer

Body is acted upon by a force given by equation F=(3 t2-30) N ∴ m(v-u)=∫ F d t =(3 t3/3)-30 t=t3-30 t =53-30(5)=125-150=-25 ∴ m[v-10]=-25 ⇒ Final velocity v=7.5 m / s

Q. A body of mass $10 k g$ is acted upon by a force given by equation $F = (3 t^{2} - 30)$ newtons. The initial velocity of the body is $10 m / s$ . The velocity of the body after $5 s$ is

4.5 m / s

6 m / s

7.5 m / s

5 m / s

Body is acted upon by a force given by equation
$F = (3 t^{2} - 30) N$
$∴ m (v - u) = \int F d t$
$= \frac{3 t ^{3}}{3} - 30 t = t^{3} - 30 t$
$= 5^{3} - 30 (5) = 125 - 150 = - 25$
$∴ m [v - 10] = - 25$
$\Rightarrow$ Final velocity $v = 7.5 m / s$

Q. A body of mass 10kg is acted upon by a force given by equation F=(3t2−30) newtons. The initial velocity of the body is 10m/s. The velocity of the body after 5s is