1. What is the weight of a 2.88 kg snake?

Question

2. A girl drops a rock straight down from a bridge. Assume negligible air resistance. How fast is it going 4.0 s later?


3. A rock with a mass of 22.45 kg is falling from a tall tower.
a. What is the Net Force if the rock is in free fall?

b. What is the Net Force if the rock experiences an air resistance of 16.44 N

c. What is the Net Force when the rock reaches its terminal velocity of – 15m/s?

4. A 75.0 kg person stands on a scale in an elevator.

a. . What does the apparent weight (scale read) when the elevator is at rest?

b. . What does the apparent weight (scale read) when the elevator is climbing at a constant speed of + 3.00 m/s?

c. . What does the apparent weight (scale read) when the elevator accelerates upwards at + 1.46 m/s2?

d. . What does the apparent weight (scale read) when the elevator accelerates downwards at - 1.46 m/s2?

5. Before a sky diver opens his parachute, he may be falling at a velocity higher than the terminal velocity he will have after the parachute opens.

a) Describe what happens to his velocity as he opens the parachute.

b) Describe his velocity from after his parachute has been open for a time until he is about
to land.

6. From the top of a tall building, you drop two tennis balls, one ball is filled with air and the
other ball is filled with lead. Both experience air resistance as they fall.

a. Which ball reaches terminal velocity first?

b. Do both balls hit the ground at the same time? Explain.

7. A book weighing - 14.55 N rests on an inclined plane at 36o from the horizontal.

a. Make a drawing of this situation. Draw and label the various force vectors

b. Find the components of the weight parallel and perpendicular to the plane.

8. A fisher in a boat is using a “10-lb test” fishing line. This means that the line can exert a force of 44 N without breaking (1 lb = 4.4 N). (Hint: make a drawing of the forces acting on the fish.)

a) How heavy a fish can the fisher catch if he pulls the fish up vertically at constant speed? (2 marks)
b) How heavy a fish can this person catch if the fish occasionally accelerates at 3.0 m/s2 downward?

Answer 1

1. Wt. = m*g = 2.88 * 9.8 = 28.2 Newtons

2. V=Vo * gt. Vo = 0,g = 9.8m/s^2,t=4s.

3. Fn = m*g.

3b. Fn = m*g - 16.44