Acceleration
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
East is positive. A cart starts at 2 m/s, accelerates at 3 m/s² for 4 s, then at -5 m/s² for 3 s. What is its final velocity, Ari?
East is positive. A cart starts at -4 m/s, accelerates at 2.5 m/s² for 6 s, then at -1.5 m/s² for 4 s. What is its final velocity, Bo?
Two cars travel at 25 m/s, 30 m apart. The lead car brakes at 6.0 m/s²; the driver behind reacts after 0.70 s and brakes the same. Do they collide, Kira?
- Yes: the follower needs 69.6 m but 30 m is free
- No: both brake equally, so the gap stays 30 m
- No: the gap shrinks by 17.5 m, leaving 12.5 m
- Yes: the 0.70 s delay uses up the whole 30 m gap
A rocket sled goes from rest to 80 m/s over 400 m at constant acceleration. What are a and the time taken, Luz?
- a = 0.20 m/s²; t = 400 s, from 80 ÷ 400
- a = 8.0 m/s²; t = 5.0 s, from 400 ÷ 80
- a = 8.0 m/s²; t = 10 s
- a = 16 m/s²; t = 5.0 s, dropping the factor 2
A town says cutting the limit from 50 to 40 km/h cuts total stopping distance by only 20%. With 0.75 s reaction time and 6.0 m/s² braking, judge it, Milo.
- Overstated: it falls 10%, since reaction time is fixed
- Understated: the total falls about 30%, from 26.5 m to 18.6 m
- Correct: 20% less speed means 20% less distance
- Understated: it falls 36%, the braking part alone
Noah says a ball falling at a steady 12 m/s in air has a = 0, so gravity has stopped acting. Judge the claim.
- Wrong: a must stay 9.8 m/s² for as long as gravity acts
- Right: a = 0 means that no force is acting on the ball
- a = 0 is right, but gravity still acts; drag balances it
- Wrong: a steady speed means that the ball is at rest
Pia says a sprinter's average acceleration over 10 s, 1.06 m/s², shows how the sprinter speeds up. The sprinter reaches 10 m/s at 2 s and 10.6 m/s at 10 s.
- Fine: an average describes each second of the race
- Fine: 1.06 m/s² lies between 0 and 10 m/s
- Misleading: a was 5 m/s² early and under 0.1 m/s² later
- Misleading: a was 1.06 m/s² early and 5 m/s² later
Constant a: a cart reads +6 m/s at t = 1 s and −4 m/s at t = 5 s. When does it turn around, Ren?
- At t = 3.4 s, 2.4 s after the +6 m/s reading
- At t = 5 s, the last reading
- At t = 3 s, halfway between the readings
- At t = 2.4 s, counting from the clock's zero
Read this first
Braking tests (example data)
speed (m/s) distance to stop (m) 10 8 15 18 20 32 Using the braking table, what is the car's constant deceleration, and how far does it need from 30 m/s, Tala?
- a = 6.25 m/s²; 72 m from 30 m/s
- a = 12.5 m/s²; 36 m, dropping the factor 2
- a = 1.25 m/s²; 72 m, from 10 ÷ 8
- a = 6.25 m/s²; 48 m, scaling the distance with speed
Zee looks at a phone for 2.0 s while driving at 25 m/s. Braking would give 7.0 m/s². Which is greater: the distance traveled blind, or the braking distance?
- The blind distance: 50 m against 44.6 m of braking
- The blind distance: 50 m against 22 m of braking
- They are equal, since 25 m/s is used for both
- The braking distance: 89 m against 50 m of blind travel