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An object orbits Earth at an altitude of 200 kilometers above the planet’s surface. What is its speed and orbital period?

To begin with, we need to draw a graph with all of the forces acting on a body. From that, we can see that the net force Fnet = Fg - Fc , where Fg is gravitational force and Fc is centripetal force acting on...
DA
Answered by Domas A. • Physics tutor
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There are 30 yellow sweets and 10 black sweets in a bag. Two sweets are taken out at random without replacement. Work out the probability that the two sweets are the same colour.

It is important before proceeding with the question to note down a few key facts. As can be seen by the question there are 40 sweets in total. With probability questions in general it can be easy to remember...
JT
Answered by James T. • Maths tutor
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Write y = x^2 + 4x + 6 in the form y = (x + a)^2 + b. What is the minimum value of y?

This is an example of completing the square. Notice that when we expand y = (x + a)^2 + b we get y = x^2 + 2ax + a^2 + b. By comparing coefficients (ie, making sure the number x is multiplied by and the cons...
NS
Answered by Naomi S. • Maths tutor
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Why was the New Economic Policy (NEP) introduced?

Lenin introduced the NEP in the aftermath of the ruinous Russian Civil War of 1917-1922. The Soviet state had pursued a policy of 'War Communism' during the war in order to keep the Red Army well provisioned...
CS
Answered by Charlie S. • History tutor
31249 Views

Find INT{2,1}{x^4 + 3x^2 + 2}

This is a typical AS-level Maths question. We see it’s a definite integral so start by drawing some big square brackets with the “limits” (2 and 1). We go through the expression inside the integral (the “int...
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Answered by Andrew F. • Maths tutor
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