Q3 Answer all of the following parts (a), (b), (c), etc. (a) What is a physical quantity?
(b) Which of the following are scalar quantities? distance
velocity
(c) Explain the term ‘vector quantity’. (d) Define velocity.
(e) Describe a velocity of 18 km h1 in SI units.
(f) What two quantities remain fixed when a body travels at constant velocity? (g) Define acceleration.
(h) Is it possible for a car travelling at constant speed to be accelerating? Justify your answer. (i) A car travels 5 km east followed by 12 km north. How far is the car from its starting position? °
time acceleration displacement (7)
(7) (7) (7) (7) (7) (7) (7) (7)
(j) A rocket has a steady velocity of 250 m s1 at an angle of 36.87 above the horizontal.What is the vertical component of its velocity?
‘SECTION B’ FULL QUESTIONS
Q4 An athlete sprints from rest and reaches a maximum velocity of 12.1 m s1 after 3 s. He maintains this velocity for 5 s before decelerating to 9.25 m s1 over the next 2 s.
(i) Draw a velocity–time graph to illustrate the athlete’s horizontal motion. (15)
(ii) Use your graph to calculate the distance travelled by the athlete over the 10 s. (13)
In the 2008 Olympics in Beijing, the Jamaican sprinter Usain Bolt broke the 100 m world record in a time of 9.69 s.
(iii) Calculate his average velocity, correct to two decimal places. (6)
(iv) He reached a top speed of 12 m s1 after 3 s. Assuming the acceleration was constant, calculate his acceleration over that period. (9)
(v) He also broke the 200 m world record in a time of 19.30 s.While running the bend in that race he was
