Question

A space craft flying in a straight course with a
velocity of 75 km - fires its rocket motors for
6-0 s. At the end of this time, its speed is
120 km s' in the same direction. Find the (i) space
craft's average acceleration while the motors were
firing, (ii) the distance travelled by the space craft
in the first 10 s after the rocket motors were started,
the motors having been in action for only 6-0 s.​

Answer 1

Answer:

average acceleration is 7.5m/s²

the distance travelled in the first 10seconds after firing rocket motors is 1065km

Explanation:

the average acceleration is the change in velocity in the time taken,

a=(120-75)/6

=45/6=7.5m/s²

the distance travelled within the10 seconds from motor start,

the motors were in action only for 6s, so the distance travelled in those 6s:

s=ut+(1/2)at²

where,

s- distance travelled

u- initial velocity

t- time taken

a- acceleration

s=75×6+(1/2)×7.5×6²

s=450+(1/2)×270

s=450+135

s=585km

distance travelled in the rest of the 4s

d=4×120

d=480km

the total distance travelled

=480+585

=1065km