Question

The graph given alongside shows how the speed of a car moving in a straight line changes with time:

(i) What is the initial speed of the car?
(ii) What is the maximum speed attained by the car?
(iii) Which part of the graph shows zero acceleration?
(iv) Which part of the graph shows varying retardation?
[5 Marks]

Speed (in km/h) —_ = DN W W N LN O L O O L O S 1 2 3 4 5 6 7 8 Time (in hours) —» 9 10 

Answer 1

(a) The initial speed of the car is the speed at t = 0. Hence, it is 10 km/ h.

(b) The maximum speed is 35 km/hr. See the points B and C.

(c) B to C shows zero acceleration as there is no change in speed of the car with respect to time.

(d) The part from C to D shows varying retardation as its speed is not decreasing uniformly with the time. (In part A to B we have uniform acceleration.)