Displacement and velocity, with a frame of reference
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
East is positive. Bo's cart rolls 100 m east at 5 m/s, then 60 m west at 2 m/s. What is its average velocity for the whole trip?
In the position-time graph, what is the cart's average velocity for the whole 12 s, Jun?
- 0 m/s, since the slopes +3, 0 and −3 average out
- −0.25 m/s, from a displacement of −3 m
- −3 m/s, the slope of the last piece
- +2.25 m/s, the total distance ÷ time
Kira's boat heads straight across a 120 m wide river at 4.0 m/s relative to the water. The current is 3.0 m/s downstream. How long to cross, and how far downstream does it land?
- 30 s, landing 90 m downstream
- 40 s, landing 120 m downstream
- 24 s, landing 72 m downstream
- 30 s, landing 120 m downstream
For the same boat, what are its speed relative to the bank and its direction measured from straight across, Luz?
- 5.0 m/s, 53° downstream of straight across
- 7.0 m/s, 37° downstream of straight across
- 1.0 m/s, 37° downstream of straight across
- 5.0 m/s, 37° downstream of straight across
Milo hikes 6.0 km east in 2.0 h, then back 6.0 km west in 3.0 h. What are the average speed and average velocity?
- Speed 0 km/h; velocity 0 km/h
- Speed 2.4 km/h; velocity 0 km/h
- Speed 2.5 km/h; velocity 0 km/h, from the mean of 3 and 2
- Speed 2.4 km/h; velocity 2.4 km/h
A drone flies 300 m east, then 400 m north, in 100 s. What are its displacement, average velocity and average speed, Noah?
- 500 m at 53° north of east; velocity 5 m/s, speed 7 m/s
- 100 m north of east; velocity 1 m/s, speed 7 m/s
- 700 m north of east; velocity 7 m/s, speed 7 m/s
- 500 m north of east; velocity 5 m/s, speed 5 m/s
Pia walks 3.0 km east, 4.0 km north, then 3.0 km west in 2.0 h. What are the displacement and average velocity?
- 10 km; 5.0 km/h
- 4.0 km north; 2.0 km/h north
- 5.0 km; 2.5 km/h
- 4.0 km north; 5.0 km/h north
East is positive. Car A drives +25 m/s and truck B +18 m/s, with B 70 m ahead. How long until A reaches B, Ren?
- 1.6 s: 70 ÷ (25 + 18)
- 3.9 s: 70 ÷ 18, ignoring A
- 10 s: A gains 7 m/s on B
- 2.8 s: 70 ÷ 25, ignoring B
The boat (4.0 m/s relative to the water) must land directly across a 120 m river with a 3.0 m/s current. How should Tala aim, and how long does it take?
- Aim 49° upstream; 30 s, using the full 4.0 m/s across
- Aim 37° upstream; about 38 s to cross
- Aim straight across; 30 s, but it lands downstream
- Aim 49° upstream; about 45 s to cross
A plane heads north at 200 m/s in air. A wind blows east at 50 m/s. What is its ground speed, and how far east does it drift in 10 min, Zee?
- 206 m/s; 120 km east
- 250 m/s; 30 km east
- 206 m/s; 30 km east
- 200 m/s; 30 km east