Assignment:
Please show all works clearly. Indicate your answers with circle using correct units and significant figures. I will give you partial credits if you show all works and solve parts of problem. You will be responsible for losing the credits if you do not show your work clearly even the final answer is correct.
Position and Displacement:
1. At 3:00 p.m. a car is located 20 km south of its starting point. One hour later it is 96 km farther south. After two more hours, it is 12 km south of the original starting point.
(a) What is the displacement of the car between 3:00 p.m. and 6:00 p.m.?
(b) What is the displacement of the car from the starting point to the location at 4:00 p.m.?
(c) What is the displacement of the car between 4:00 p.m. and 6:00 p.m.? Speed and Velocity:
2. Joe travels 1.5 km from his home to the school in 20 min, and returns home in 30 min. What is his average speed (m/s) for the entire trip?
3. A race car travelling northward on straight track travels 750 m in 20.0 s. The return trip is made in 25.0 s. What is the average speed and average velocity of the car in m/s for the total trip?
4. A jogger jogs around a circular track with a diameter of 300 m in 10 minutes. What was the jogger's average speed and average velocity?
5. SF Jason drives due west with a speed of 35.0 mi/h for 30.0 min, then continues in the same direction with a speed of 60.0 mi/h for 2.00 h, and then drives still farther west at 25.0 mi/h for 10.0 min. What is Jason's average velocity for the entire trip?
6. How far does the object move from t = 0 to t = 3 s?
7. The graph shows x(t) for an object traveling along the x-axis. Plot vx as a function of time for this object from t = 0 to t = 8 s.
8. Rita Jeptoo of Kenya was the first female finisher in the 110th Boston Marathon. She ran the first 10.0 km in a time of 0.5689 h. Assume the race course to be along a straight line.
(a) What was her average speed during the first 10.0 km segment of the race?
(b) She completed the entire race, a distance of 42.195 km, in a time of 2.3939 h. What was her average speed for the race?
Acceleration:
9. If a car traveling at 28 m/s is brought to a full stop in 4.0 s after the brakes are applied, find the average acceleration during braking.
10. An airplane starts from rest; 8.0 s later it reaches its takeoff speed of 35 m/s. What is the average acceleration of the airplane during this time?
11. Sketch a graph of ax (t) for the car in
Equation of motion with constant acceleration
12. You are driving your car along a country road at a speed of 27.0 m/s. As you come over the crest of a hill, you notice a farm tractor 25.0 m ahead of you on the road, moving in the same direction as you at a speed of 10.0 m/s. You immediately slam on your brakes and slow down with a constant acceleration of magnitude 7.00 m/s2. Will you hit the tractor before you stop? How far will you travel before you stop or collide with the tractor? If you stop, how far is the tractor in front of you when you finally stop?
Free Fall
13. (a) How long does it take for a golf ball to fall from rest for a distance of 12.0 m?
(b) How far would the ball fall in twice that time?
14. Grant jumps 1.3 m straight up into the air to slam-dunk a basketball into the net. With what speed did he leave the floor?
15. During a walk on the Moon, an astronaut accidentally drops his camera over a 20.0 m cliff.
It leaves his hands with zero speed, and after 2.0 s it has attained a velocity of 3.3 m/s downward. How far has the camera fallen after 4.0 s?
16. A 55 kg lead ball is dropped from the leaning tower of Pisa. The tower is 55 m high.
(a) How far does the ball fall in the first 3.0 s of flight?
(b) What is the speed of the ball after it has traveled 2.5 m downward?
(c) What is the speed of the ball 3.0 s after it is released?
(d) If the ball is thrown vertically upward from the top of the tower with an initial speed of 4.80 m/s, where will it be after 2.42 s?