A car is travelling at 10m/s when it brakes and decelerates at 2ms^-2 to a stop. How long does the car take to stop?
This is a question testing the knowledge of the equations of constant acceleration (Suvat equations)First convert the question into a standard form. For example by writing out the variables as follows s (displacement) = unknownu (initial velocity) = 10m/sv (final velocity) = 0m/sa (acceleration) = 2ms^-2t (time) = unknownYou know v, u and a and you want to calculate t, therefore the equation you need to use is v = u + a*tRe-arranging t = (v - u) / a Finally substituting in v, u and a, t = (10 - 0) / 2 = 5sSo the time taken for the car to stop is 5 seconds.
KM
Related Physics A Level answers
All answers ▸A box initially at rest is on a plank, of length 5m, that is elevated at an angle such that tan(a)=3/4. When it reaches the end of the plank it has velocity 5ms^-1. Calculate the average frictional force on the box.
On the line of centres between the Earth and the Moon, there is a point where the net gravitational force is zero. Given that the distance between the two is 385,000 km, and that the Earth has a mass 81x that of the Moon, how far is this point from Earth?
How and why does a geostationary satellite stay above the same point on the Earths surface?
A ball of mass 0.7 kg strikes the wall at an angle of 90 degrees with speed 72 km/h. Consider that the bounce lasts for 0.1 s and is perfectly elastic. What is the magnitude of the average reaction force from the wall that acts on the ball?