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## Homework Statement

Hi im new to these forums but i have been trying for about 2 days now and still cannot find the answer to these 4 questions if someone could please help me it would be greatly appriciated! i come from a different country this is my third month in Canada, and i am doing an online course.

these are the questions

7. A stationary elevator and its contents have a combined mass of 3000 kg. The elevator is suspended by a single cable. (Assume three significant digits.)

1. Draw a free-body diagram of the elevator and calculate the values of all the forces that are acting on it when at rest.

2. If the elevator is ascending at a speed of 3.0 m/s, what are the values of the forces acting at this point?

3. If the elevator is descending at 3.0 m/s2, what are the values of all the forces acting at this point?

8. A force of 1.6 N is applied to a box of mass 1.8 kg. It accelerates at 0.60 m/s2. Determine the force of friction that is acting and the coefficient of kinetic friction involved.

9. A desk of mass 45 kg is pushed across a rough surface (mK = 0.18) for a distance of 2.0 m by a constant force of 50 N. If the desk reaches a speed of 1.0 m/s by the end of the push, what was its speed at the beginning of the push? (Assume two significant digits.)

10. An object of mass 60.0 kg rests on the surface of a planet with a mass of 7.7 × 1022 kg and radius 4.6 × 105 m.

1. Calculate the force of gravity acting on the object.

2. Determine the gravitational field strength "g" at the planet's surface.

3. Calculate the force of gravity acting on the object if it is placed at a position 6.6 × 105 m above the planet's surface.

## Homework Equations

f=ma

## The Attempt at a Solution

With question 7 i drew the free body diagram as the elevator has 9.8m/s2 down because of gravity.

Then i put

f=ma

f=(3000)(9.8)

f=29400 N

thats all i got and for the other questions, i have gotten no other formulas i am very confused please help!