Twenty Questions Kinematics

Twenty Questions

1. What formula relates speed, distance and time? v = d / t speed = distance/time

2. What is deceleration? an object slowing down. negative acceleration.

3. What is the difference between scalars and vectors? scalar has magnitude, only. vector has both magnitude and direction.

4. Calculate distance travelled. d = area under v-t graph d = ½ bh + lb + lb + ½ bh d =½5x4 +4x5 +13x8 +½2x8 d = d = 142m v(m/s) t(s)

5. A girls jogs 2km North, then turns & jogs 1.6km South. She does this in 10mins. What is her speed? v = d/t v = 3600/600 v = 6ms -1

v = s/t v = 400/600 v = 0.67ms -1 North 6. A girls jogs 2km North, then turns & jogs 1.6km South. She does this in 10mins. What is her velocity?

7. A train accelerates from 20ms -1 to 30ms -1 in 2.5s. What is the trains acceleration? a = v - u = 30 – 20 t 2.5 a =4ms -2

8. Describe the motion between B and C. The vehicle travels at constant speed. Zero acceleration. v(m/s) t(s) D A B C

9. A Harley Davidson accelerates, from rest, at 2.5ms -2 to 30ms -1 in 10s. What was the bike’s initial speed? a = v - u t 2.5 = 30 – u 2 u =25ms -1

10. Calculate the acceleration between 18s and 20s. a = v - u = 0 – 8 t 2 a =-4ms -2 v(m/s) t(s)

11. A cross-country runner runs 200m North then 1km East. What is the runners displacement? Scale 1cm:200m s = 1020m at 79 o a 2 = b 2 + c 2 a = √ a = m s = m at o tanθ = O/A = 1000 ÷ 200 = 5 θ = 78.7

12. A bus accelerates at 3ms -2 from rest to 30ms -1. How long does this take? a = v - u t t = v - u = 30 – 0 a 3 t = 10s

13. A bike accelerates at 5m/s 2 from rest for 15s. What is it’s final speed? a = v - u t v = u + at = 0 + 5x15 v = 75m/s

14. Describe the motion between A&B. Vehicle is accelerating. v(m/s) t(s) D A B C

15. What is the formula for velocity? v = s / t velocity = displacement time

16.Describe the motion between C&D. v(m/s) t(s) D A B C The vehicle decelerates.

17. How is the apparatus shown, used to find the instantaneous speed of the trolley at the bottom of the ramp? Use light gate and timer to find time, t. Length of mask, d. v = d / t Light gate Timer Ramp Trolley

18. What is the acceleration of an object moving at a steady speed? 0ms -2

19. Which car has the smallest acceleration? Renault. CarTime for 0-60Max speed Porsche Ford Renault Bentley

20. Calculate the acceleration. a = v - u = 8 – 4 t 5 a = 0.8ms -2 v(m/s) t(s)