Question

A $1.0kg$ box on a horizontal surface experience a $3.0N$ horizontal frictional force.
How much force must be applied horizontally to the box to cause it to accelerate at $1.0m/s^2$?

• A. $1.0N$
• B. $2.0N$
• C. $3.0N$
• D. $4.0N$
• E. $5.0N$

Answer 1

Answer: (D)

$4.0N$

Let F be the applied force to the box.

From FBD, $ma=F-f$

So, $F=ma+f=1\left(1\right)+3=4N$

Thus , option D will be correct.