Question

A van of mass 1200kg is moving with speed of 90km/hr. It is brought in 3 seconds by applying brakes. Calculate the force applied to bring van to rest. ​

Answer 1

Answer:

Explanation:

The main equation to solve this is F = ma, where F is the force applied to the brakes with respect to its acceleration. We have the mass that we need, but we do not have the acceleration. That's the first thing we have to find. However, our velocity needs to be stated in m/s and right now it's in km/h. Converting that:

$90\frac{km}{hr}*\frac{1000m}{1km}*\frac{1hr}{3600s} =25\frac{m}{s}$ Now we're ready to find the acceleration:

$a=\frac{v_f-v_0}{t}$ where the top line there translates to the final velocity minus the initial velocity.

$a=\frac{0-25}{3.0}$ so the acceleration is -8.3 m/s/s

We can use that now in the force equation above:

F = 1200(-8.3) and

F = -1.0 × 10⁴ N (that's 10,000 N to the correct number of sig dig's; the negative sign means that the force is being applied in the direction opposite to that which the van is currently moving)