madeeeeee
Nov17-10, 07:24 PM
12. A ball is thrown vertically upward from a roof of a school that is 20 m high. The equation which gives its height above ground, in metres, after t seconds, is h(t) = - 4.9t2 + 3t + 20,
a) Calculate the average rate of change of the ball between 1 and 4 seconds. [2 marks]
answer:
h(4)-h(1) / 3
-3.6 m/s
is this right?
b) Determine the instantaneous rate of change when t = 1 s. [4 marks]
answer:
h(t) = - 4.9t2 + 3t + 20
h'(t)= -9.8t + 3
= -9.8(1) + 3
= -6.8 m/s
At t= 1s, the skydiver is falling at a rate of -6.8 m/s.
is this right?
a) Calculate the average rate of change of the ball between 1 and 4 seconds. [2 marks]
answer:
h(4)-h(1) / 3
-3.6 m/s
is this right?
b) Determine the instantaneous rate of change when t = 1 s. [4 marks]
answer:
h(t) = - 4.9t2 + 3t + 20
h'(t)= -9.8t + 3
= -9.8(1) + 3
= -6.8 m/s
At t= 1s, the skydiver is falling at a rate of -6.8 m/s.
is this right?