Compare designs that reduce the force in a collision
Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.
A 2 kg toy cart at 3 m/s must be stopped with an average force of no more than 15 N. How long must the stop last, Ari?
A 4 kg toy cart at 2 m/s must be stopped with an average force of no more than 10 N. How long must the stop last, Bo?
A 0.5 kg toy cart at 6 m/s must be stopped with an average force of no more than 5 N. How long must the stop last, Esme?
In the bar chart, what are the average forces for the hard and soft stops, Kira?
- Hard 0.3 N, soft 1.5 N
- Hard 24 N, soft 120 N
- Both 6 N
- Hard 120 N, soft 24 N
Bumper tests on a 2 kg toy cart at 3 m/s (example data). Columns: bumper, stop time (s), average force (N), bounces back?, added mass (g). A, foam, 0.2, 30, no, 50; B, spring, 0.1, 120, yes, 80; C, wood, 0.02, 300, no, 40; D, thick foam, 0.4, 15, no, 150. Bumper tests on a 2 kg toy cart at 3 m/s (example data). Columns: bumper, stop time (s), average force (N), bounces back?, added mass (g). A, foam, 0.2, 30, no, 50; B, spring, 0.1, 120, yes, 80; C, wood, 0.02, 300, no, 40; D, thick foam, 0.4, 15, no, 150. Bumper tests on a 2 kg toy cart at 3 m/s (example data) bumper stop time (s) average force (N) bounces back? added mass (g) A, foam 0.2 30 no 50 B, spring 0.1 120 yes 80 C, wood 0.02 300 no 40 D, thick foam 0.4 15 no 150 Using the bumper table, with force under 50 N and added mass at most 100 g, why isn't D chosen, Milo?
- It stops the cart too slowly to count
- It bounces the cart back
- It adds 150 g, over the limit
- Its force is too high
Using the bumper table, a classmate picks C because it is lightest. Why does C fail, Noah?
Use the picture in question 5.
- It bounces the cart back
- It is the right pick, being lightest
- It is too heavy
- Its 300 N force breaks the force limit
Using the bumper table, a classmate picks D because its force is lowest. What should Pia point out?
Use the picture in question 5.
- D's force is too high
- D bounces the cart back
- D wins on force, so pick it
- D breaks the 100 g mass limit
Why should every bumper be tested with the same cart at the same speed, Ren?
- To make the test quicker
- So only the bumper changes
- To raise the force
- So the bumpers wear out evenly
Why should each bumper be tested several times, Tala?
- To check the results are reliable
- To lower the force
- To change the cart's mass between runs
- To make the cart faster
A very thin, soft foam bumper squashes completely flat in a test. What problem does that cause, Zee?
- The force drops to zero
- The cart stops suddenly at the end, with a big force
- The cart bounces back faster
- Nothing; flat foam works well