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Physics
A Level

How can an object be accelerating when it's velocity is constant, and how does centripetal acceleration work.

Although an object in circular motion travelling at constant velocity isn't accelerating in the conventional sense, ie. changing speed, it's important to remember that it is a vector. Vector quantities ha...

Answered by Tom G. Physics tutor
2597 Views

Derive Keplers 3rd law

Equate gravitational force (GMm/r^2) to centripetal force (mv^2/r). Rearrange to get v^2=GM/r. Due to the approximated circular orbit v=2pir/T so v^2=4pi^2r^2/T^2. Therefore GM/r=4pi^2r^2/T^2. Rearrangin...

Answered by Michael S. Physics tutor
2998 Views

A projectile is fired at an angle of 30 degrees from the horizontal, it reaches a maximum height of 12m above the ground before coming to rest 600m from its initial starting point at the same level. What is the initial speed of the projectile?

At first glance this question seems require solving in several steps, splitting horizontal and vertical components, taking a value for time from the motion under constant acceleration and then applying th...

Answered by Joseph S. Physics tutor
8111 Views

A geostationary satellite is orbiting Earth, a) What is meant by a geostationary orbit? b) Calculate the height at which the satellite orbits above the surface of the Earth. The radius of the Earth is 6400km and its mass is 6x10^24 kg.

a) A geostationary orbit is when the satellite remains vertically above the same point on the equator at all all times and consequently has an orbital period of 24 hours. b) Use the equation T^2=4(PI)^2(r...

Answered by Edward N. Physics tutor
18513 Views

A DVD is dropped from rest. The DVD does not reach terminal velocity before it hits the ground. Explain how the acceleration of the DVD varies from the instant it is dropped until just before it hits the ground.

In the instant when the DVD is dropped, it will have an acceleration of g, with no drag force acting on it as it is not moving. As the DVD accelerates downwards, the drag force acting on it increases and ...

Answered by Dylan H. Physics tutor
3271 Views

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