You have landed on Mars, and observe that it takes a stone 1.8 sec to fall 6 m. (A) What is the acceleration of gravity on Mars?
(B) How much does a 2 kg stone weigh on Mars?
(C) If you could jump to a height of 1.5 m on Earth, how high can you jump on Mars?
(D) If you knew that the mass of Mars was 6.4 x 1023 kg, what would you deduce is its radius?
(E) The Martian moon Deimos has a mass of 3 x 10-9 that of Mars itself. If Deimos is 2.3 x 107 m away from Mars, how strongly does Mars pull on its small satellite?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

In a system with only a single force acting upon a body, what is the relationship between the change in kinetic energy and the work done by the force? answers: work is equal to the change in kinetic energy.work depends on the square of the change in potential energy.work is equal to the negative of the change in kinetic energy.work is equal to the square of the change in kinetic energy

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.