Question

A kid is on a stationary sled, onsnowy ground withus= 0.105.It takes 71.2 N of force to setthe sled moving. How muchnormal force is acting?(Unit = N)

Answer 1

We are given the following configuration:

Where:

$\begin{gathered} N=\text{ normal force} \\ F_f=\text{ force of friction} \\ W=\text{ weight} \\ F=\text{ pulling force} \end{gathered}$

Since we are given the force to set the body in motion this means that the pulling force is equal to the friction force, therefore, we have:

$F=F_f$

The friction force is given by the following formula:

$F_f=\mu N$

Substituting we get:

$F=\mu N$

Now, we solve for the normal force by dividing both sides by the coefficient of friction:

$\frac{F}{\mu}=N$

Now, we plug in the values:

$\frac{71.2N}{0.105}=N$

Solving the operations:

$678.1N=N$

Therefore, the normal force is 678.1 Newtons.