A Car of mass 1000kg applies a constant 200N breaking force over a distance of 30m and comes to a complete stop. How fast was the car going the instant the brakes were engaged.
Before we start we should have some idea of the route of our solution. We should observe that force, distance and work have a relation and that mass, velocity and work have a relation. So we should calculate the work done by the brakes stopping the car. W=FD so W = 20030=6000J We know work = change in energy and that the final energy is 0. So we now know that the starting energy of the car KE = 6000J We now look to the kinetic energy equation that states KE = 1/2 * m * v^2 solving for v we have v=sqrt(2KE/m) we now just plug in v = sqrt(26000/1000) = sqrt(12) = 3.46 ms^-1
SO
Related Physics GCSE answers
All answers ▸Assuming no friction, describe the motion of a simple pendulum released from rest at t=0 at amplitude A? Provide information about its speed and position at characteristic times during one period. [The 1D equation of motion is described by a cosine]
An apple is suspended a string and a spring in parallel. When the string is cut, the apple falls, and the spring stretches and contracts repeatedly as the apple bounces. Describe the energy conversions that occur during this process.
What are the changes in energy that an object experiences when it is launched vertically at a given velocity into the air and falls back to the ground? This question ignores air resistance.
A mass of 2kg is dropped from rest at a height of 10m. i) What is the initial GPE of the mass? ii) What is the final velocity of the mass when it hits the ground?