10 minutes maximum! Can you do it in 5?
1. Which of these is the correct formula for speed?
2. A tortoise is pretty slow, only covering 100 cm in 50 seconds. It therefore has a speed of:
3+4. A cheetah can run at a top speed of 30 m/s.
4. How long would it take the cheetah to cover 600 m?
5. Which of these is the correct formula for acceleration?
6. What are the correct units for acceleration?
starting velocity (m/s)
final velocity (m/s)
10. A toy car accelerates across the floor at 2 m/s2. After 3 seconds the velocity is 10 m/s. What was the starting velocity?
Question 1:
The correct formula for speed is:
C. speed = distance ÷ time
A → distance × time is incorrect (that gives no standard physical quantity).
B → distance × acceleration is incorrect.
D → distance ÷ acceleration has units of time², not speed.
So the answer is C.
*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret. Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.
Question 2:
Let's calculate the speed step by step.
Given: Distance = 100 cm Time = 50 s
Formula:
The answer is B. 2 cm/s.
Question 3:
We can calculate the distance using the formula:
Given: Speed = 30 m/s Time = 5 s
The correct answer is C. 150 m.
Question 4:
We can calculate the time using the formula:
Given: Distance = 600 m Speed = 30 m/s
The correct answer is A. 20 s.
Question 5:
The correct formula for acceleration is:
D. acceleration = change in velocity ÷ time
A → velocity × time gives displacement, not acceleration.
B → change in velocity × time is incorrect (no standard quantity).
C → velocity ÷ time would be acceleration only if starting from rest (but that’s not the general definition). The general definition requires change in velocity, not just final velocity.
So the correct choice is D.
Question 6:
The correct units for acceleration are:
D. "metres per second squared" (m/s²)
A. "metres per second" (m/s) → units for velocity, not acceleration.
B. "metres seconds" (m·s) → no standard physical meaning in this context.
C. "metres seconds squared" (m·s²) → incorrect order; that would be metres × seconds², not acceleration.
Reason: Acceleration = change in velocity ÷ time. Velocity has units of m/s, dividing by time (s) gives m/s², which is read as "metres per second squared."
Question 7:
We use the acceleration formula:
Given: u=0, v=20, t=5 (where u= starting velocity and v = final velocity)
✅ Missing number: 4
Question 8:
Given: a=3, u=0, v=30 (where u= starting velocity and v = final velocity)
3=(30−0)/t = 30/t
t=30/3=10 m/s
✅ Missing number: 10
Question 9:
Given: a=4, u=5, t=10 (where u= starting velocity and v = final velocity)
4=(v−5)/10
v−5=40
v=45 m/s
✅ Missing number: 45
Question 10:
Given: a=2 m/s2 v=10 m/s t=3 s
Multiply both sides by 3:
6=10−u
u=10−6=4 m/s
The correct answer is D. 4 m/s.