(a) An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. When the elevator is accelerating upward, which is greater, T or w

T is greater

Explanation:

Since the elevator is moving against gravity more work will be done on the rope

T= m(g+a)

T is greater when the elevator is accelerating upwards.

Explanation:

The tension in the cable is given by the formula

T = m(g+a)

Taking upwards as positive, when the elevator is accelerating upwards a is positive and and g+a is greater than g

So the tension is greater than the weight mg.

But when the elevator is accelerating downwards the, the acceleration a is negative and g +a in the equation above is less than g and as a result the Tension force T is less than the weight w.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y