A car of mass 1500kg is travelling at 10 ms-1 along a horizontal road. A brake force of 3000N brings it to rest. Calculate the deceleration of the car and the distance travelled by the car whilst decelerating.
To calculate the deceleration of the car we must re-arrange F=ma to make a the subject of the formula, a = F/m. We then put in the numbers to get, 3000/1500, to get a deceleration of 2 ms^-2.
To get the distance the car has travelled we need to use one of our SUVAT equations. We know initial velocity, u = 10, the final velocity, v = 0 as the car is at rest, the acceleration, a = -2, and we want to find the distance, s. We therefore select the equation with these terms in which is v^2 = u^2 + 2as. We re-arrange to make s the subject of the formula, (v^2 - u^2)/2a = s, and sub in the numbers, to get -(10^2)/2*-2 = 25m.
Related Physics A Level answers
All answers ▸What's the difference between inertial and gravitational mass?
If a bulb has a current of 20mA and voltage of 5V, and the current cost of electricity is £3 for a kW/hour. How much money would you spend to power the bulb for 8 hours? Are these good estimates for the current, voltage and cost of electricity?
A car of mass m travelling with a velocity v comes to rest over a distance d in time t. The constant frictional force acting on the car while it is braking is found using:
Describe and explain the photoelectric effect in terms of photons interacting with the surface of a metal.