Solve for speed, distance or time
Grade 8 Science Worksheet
Circle the best answer, or write your answer on the line.
A train carries Bo 360 m at a steady 72 km/h. To change km/h to m/s, divide by 3.6. How many seconds does that take?
Esme rides in a car that keeps a steady 54 km/h for 540 m. To change km/h to m/s, divide by 3.6. How many seconds is that?
Jun walks 60 m at 2 m/s, then jogs the next 60 m at 6 m/s. What is the average speed for the whole trip?
Kira bikes 144 m uphill at 6 m/s, then 144 m downhill at 12 m/s. What is the average speed for the whole ride?
Luz's scooter goes 120 m at 4 m/s, then 120 m at 12 m/s. What is its average speed over the whole 240 m?
During which interval is the object's speed greatest, Milo?
- 10 to 20 s, when the object is 20 m from the start
- 20 to 30 s, which gains 30 m in 10 s, the steepest piece
- 0 to 10 s, since it is the first piece
- The three are equal, since the line does not go down
What is the object's average speed over all 60 s, Noah?
- 3 m/s, the speed of its first piece
- 2 m/s: it travels 60 m out and 60 m back in 60 s
- 0 m/s, since it ends where it started
- 60 m/s, since the highest point is 60 m
How far does the object travel between 5 s and 20 s, Pia?
- 45 m, the distance of the first two pieces
- 15 m
- 0 m, since the object is stopped from 10 s to 30 s
- 30 m, its distance from the start at 20 s
Read this first
Three runners (example data)
runner distance (m) time (s) A 120 20 B 150 30 C 90 18 Each runner kept a steady speed. Which runner is fastest, Ren?
- B, since B ran the farthest of the three runners
- The three are equal, since each of them ran steadily
- A: it runs 6 m/s, while B and C each run 5 m/s
- C, since C took the least time of the three runners
Two riders (example data)
traveler speed cyclist 12 km/h runner 4 m/s A cyclist rides at 12 km/h and a runner at 4 m/s. Who is faster, Tala?
- They are equal, since 12 divided by 3 is exactly 4
- The runner: 12 km/h is about 3.3 m/s, under 4
- The cyclist, since 12 is more than 4 in the table
- Cannot tell, since the two units are different