A runner moving at 5 m/s accelerates at a constant 2 m/s² for 4 s. Calculate the runner's displacement, in m.
Here is a go-kart crossing a line at 3 m/s.
It covers the next 40 m in 4 s. What acceleration did that take? The unknown is a — and in Δx = v₀t + ½at², the a sits inside the second term.
Three moves free a: take v₀t from both sides, multiply both sides by 2, then divide both sides by t².
Now solve the go-kart question with the same steps as always.
1. Write down the values in the question, and mark the unknown.
A car moving at 4 m/s covers 60 m in 5 s while its acceleration stays constant. What is that acceleration, in m/s²? Enter the number only.
A rowing shell gliding at 9 m/s covers only 24 m in the next 4 s while its acceleration stays constant. What is that acceleration?
Write down the values in the question:
Δx = 24 m
v₀ = 9 m/s
t = 4 s
Write down the equation:
Δx = v₀t + ½at²
Make a the subject:
a = 2(Δx − v₀t) / t²
Compute the v₀t term:
v₀t = 9 × 4 = 36 m
Substitute in the values, and calculate:
a = 2 × (24 − 36) / 4²
a = 2 × (−12) / 16
a = −1.5 m/s²
The shell covered less than the 36 m its starting velocity alone would have covered, so it was slowing.
A motorcycle moving at 6 m/s covers 36 m in 3 s while its acceleration stays constant. What is that acceleration, in m/s²? Enter the number only.
A truck moving at 12 m/s covers 50 m in 5 s while its acceleration stays constant. What is that acceleration, in m/s²? Include the sign in your answer.
Back to the go-kart: it crossed the line at 3 m/s and covered 40 m in 4 s. We now know its acceleration was 3.5 m/s² — worked out from nothing but a stopwatch and the length of the track.
A car moving at 6 m/s covers 60 m in 4 s while its acceleration stays constant. What is that acceleration, in m/s²? Enter the number only.
A van moving at 8 m/s covers 70 m in 5 s while its acceleration stays constant. What is that acceleration, in m/s²? Enter the number only.
A tractor moving at 10 m/s covers 42 m in 6 s while its acceleration stays constant. What is that acceleration, in m/s²? Include the sign in your answer.