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Car 1 has a of mass 1000kg and is going at 20m/s. Car 2 has the same mass as Car 1 and is stationary. If they collide and travel together as one unit in the same direction as Car 1 was going, calculate the speed of the unit after the collision.

By Conservation of Momentum Total Momentum Before= Total Momentum After thus m1v1+m2v2=(m1+m2)v3 Plugging in the numbers and re-arranging for v3 gives 1000 20+1000 0=2000*v3 v3=(1000*20)/2000=10m/s
AH
Answered by Aamir H. • Physics tutor
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What is gravitational potential energy? Why is it negative?

We define gravitational potential as: the work done to bring a small "test" mass from infinity to a point. But what does this truly mean? The "work done" is simply the energy we need to p...
AS
Answered by Alexander S. • Physics tutor
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A 100g mass is on a circular turntable spinning at 78 revolutions per minute. The maximum frictional force between the mass and turntable is 0.50N. Find the maximum distance from the center of the turntable at which the mass would stay on the turntable.

First, draw a diagram as it makes the problem easier to understand. Show the turntable and mass. Label the distance between the mass and the centre of the turntable r as it is a radius. write down all variab...
AC
Answered by Amy C. • Physics tutor
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The braking distance of a road train travelling at 15m/s is 70m. Assuming that the same braking force is applied at all speeds, show that the braking distance of a road train when travelling at 25m/s is about 190m.

Energy = force x distance and Energy = 0.5 x mass x velocity squared Hence, force = (0.5 x mass x velocity squared) / distance --- (equation 1) This applies for both situation A and B, and given that force i...
JJ
Answered by Jack J. • Physics tutor
10795 Views

What is a moment?

A moment about a point is the product of a force applied and the distance perpendicular to the line of action of that force. So M = F*d
KT
Answered by Kieran T. • Physics tutor
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