Practice problems midterm 1
Phys2A: Practice problems for the 1st midterm test
Fall 2013
0.674
to the proper number of significant figures?
0.74
1.
What is
Answer: 0.91
2.
A 8.7 hour trip is made at an average speed of 73.0 km/h. If the first third of the trip
(chronologically) was driven at 96.5 km/h, what was the average speed for the rest of the journey? Answer: 61 km/h
3.
A car travels 95 km to the north at 70.0 km/h, then turns around and travels 21.9 km at
80.0 km/h. What is the difference between the average speed and the average velocity on this trip?
Answer: 27 km/h
4.
A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed of 450 m/s and emerges with a speed of 220 m/s, what is the bullet’s acceleration as it passes through the board? Answer: –550 km/s2
5.
A particle confined to motion along the x axis moves with constant acceleration from x = 2.0 m to x = 8.0 m during a 2.5s time interval. The velocity of the particle at x = 8.0 m is 2.8 m/s. What is the acceleration during this time interval? Answer: 0.32 m/s2
6.
A package is dropped from a helicopter moving upward at 15 m/s. If it takes 16.0 s before the package strikes the ground, how high above the ground was the package when it was released? (Disregard air resistance.) Answer: 1000m
7.
A tennis ball gun launches tennis balls at 18.5 m/s from ground. it is pointed straight up and launches one ball; 2.0s later, it launches a second ball. What is the height above ground these two balls meet in air? Answer: 13m
8.
If vector B is added to vector A, the result is 6i + j. If B is subtracted from A, the result is
–4i + 7j. What is the magnitude of A? Answer: 4.1
9.
Starting from one oasis, a camel walks 25 km in a direction 30° south of west and then walks 30 km toward the north to a second oasis. What is the direction from the first oasis to the second oasis? Answer: 51° W of
Fall 2013
0.674
to the proper number of significant figures?
0.74
1.
What is
Answer: 0.91
2.
A 8.7 hour trip is made at an average speed of 73.0 km/h. If the first third of the trip
(chronologically) was driven at 96.5 km/h, what was the average speed for the rest of the journey? Answer: 61 km/h
3.
A car travels 95 km to the north at 70.0 km/h, then turns around and travels 21.9 km at
80.0 km/h. What is the difference between the average speed and the average velocity on this trip?
Answer: 27 km/h
4.
A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed of 450 m/s and emerges with a speed of 220 m/s, what is the bullet’s acceleration as it passes through the board? Answer: –550 km/s2
5.
A particle confined to motion along the x axis moves with constant acceleration from x = 2.0 m to x = 8.0 m during a 2.5s time interval. The velocity of the particle at x = 8.0 m is 2.8 m/s. What is the acceleration during this time interval? Answer: 0.32 m/s2
6.
A package is dropped from a helicopter moving upward at 15 m/s. If it takes 16.0 s before the package strikes the ground, how high above the ground was the package when it was released? (Disregard air resistance.) Answer: 1000m
7.
A tennis ball gun launches tennis balls at 18.5 m/s from ground. it is pointed straight up and launches one ball; 2.0s later, it launches a second ball. What is the height above ground these two balls meet in air? Answer: 13m
8.
If vector B is added to vector A, the result is 6i + j. If B is subtracted from A, the result is
–4i + 7j. What is the magnitude of A? Answer: 4.1
9.
Starting from one oasis, a camel walks 25 km in a direction 30° south of west and then walks 30 km toward the north to a second oasis. What is the direction from the first oasis to the second oasis? Answer: 51° W of