Question

A 1000kg truck traveling at 108km/h skids 10m before it stops. What is the magnitude of the frictional force acting on the car?

Answer 1

Given that,

Mass of truck = 1000 kg

Speed = 108 km/h = 30 m/s

Distance = 10 m

We need to calculate the acceleration

Using equation of motion

$v^2=u^2+2as$

Where, v = final speed

u = initial speed

s = distance

Put the value into the formula

$(0)^2=30^2+2\times a\times 10$

$a=-\dfrac{30^2}{2\times10}$

$a= -45 m/s^2$

We need to calculate the magnitude of the frictional force acting on the truck

Using formula of force

$F=ma$

Where, m = mass of truck

a = acceleration

Put the value into the formula

$F=1000\times(-45)$

$F= -45000\ N$

Negative sign shows the opposite direction of motion.

Hence, The magnitude of the frictional force acting on the truck is 45000 N.