Question

A constant horizontal force of 20N acts on a body on a smooth horizontal plane.The body starts from rest and is observed to move 20m in two seconds .The mass of the body is

Answer 1

F=20n
v=20/2m/s or 10 m/s
u=0 m/s
t=2 sec
thus . v =u +at
10=0 + 2a
a=5m/s²
thus .
f=ma
20=m*5
thus . m =4 kg

Answer 2

Answer:

Mass, m = 2 kg

Explanation:

Given that,

Horizontal force acting on the body, F = 20 N

Initial speed of the body, u = 0

Distance covered, d = 20 m

Time taken, t = 2 s

Let a is the acceleration of the body. Using the second equation of motion as :

$d=ut+\dfrac{1}{2}at^2$

$20=\dfrac{a}{2}\times (2)^2$

$a=10 m/s^2$

The formula for the force acting on the body is given by :

F = m a

$m=\dfrac{F}{a}$

$m=\dfrac{20}{10}$

m = 2 kg

So, the mass of the body is 2 kg. Hence, this is the required solution.