A block of mass 3 kg which is at rest on a surface is pulled horizontally by a force. If the displacement of the block is 15 m in the first 3 s and the surface offers a resistance of 2 N, find the sequence of steps to calculate the magnitude of applied force.
(a) Note down the values of s, u, t and frictional force
(b) The applied force on the block is the sum of frictional force and net force
(c ) Substitute the values of s, u and t in the equation of motion nad solve for 'a'
(d) Using Newton's second law of motion, calculate the net force acting on the block.

Options

A. a d b c
B. a c b d
C. a c d b
D. a b d c

Answer

C

Explanation

Given m = 3 kg
s = 15 m
t = 3 s
u = 0
Frictional force, `f_(f) = 2 N`. (a)
`15 = 0 xx 3 + (1)/(2) xx a xx 3^(2)`
`a = (10)/(3) m s^(-2)`
`F_("net") = ma = 3 xx (10)/(3) = 10 N`
`F_(a) = F_("net") + F_(f) = 10 + 2 = 12N(b)`