Question 84: Laws of Motion

Question

A force acts for 20 s on a body of mass 20 kg, starting from rest, after which the force ceases and then body describes 50 m in the next 10 s. The value of force will be:

Accepted Answer

$$m = 20$$ kg
$$t = 20$$ sec.
Acceleration $$ = {F \over {20}}$$ m/s$$^2$$
$$	herefore$$ $$v = u + at$$
$$v = 0 + \left( {{F \over {20}}} ight)(20)$$
$$ = F$$ ms$$^{-1}$$
Now for next 10 sec.
$$S=ut$$
$$50=F(10)$$
$$F=5$$

Answer

40 N

Answer

20 N

Answer

5 N

Answer

10 N

Laws of Motion

A force acts for 20 s on a body of mass 20 kg, starting from rest, after which the force ceases and then body describes 50 m in the next 10 s. The value of force will be:

Choose the correct answer: