Question

11. A motorbike, initially at rest, picks up
velocity of 72 km h-' over a distance
40 m. Calculate (i) accelearation (ii) time in
which it picks up above velocity.
12. A cyclist driving at 5 ms- picks a velocity
of 10 ms-, over a distance of 50 m.
Calculate (i) acceleration (ii) time in which
the cyclist picks up above velocity.
13. An aeroplane lands at 216 km h- and stops
after covering a runway of 2 km. Calculate
the acceleration and the time, in which it
comes to rest.
A truck running at 90 km h-!, is brought to
rest over a distance of 25 m. Calculate the
retardation and time for which brakes are
applied.
A racing car, initially a
velocity of 180 km h
(i) acceleration (ii) d
A motorbil
velocity
nir
(i)
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Answer 1

Answer:

Explanation:

(I)Initial velocity (u)=0

Final velocity (v)=72km/h

Distance. (s)=40m

Acceleration. (a)=?

v= 72km/h convert into m/s

72×1000/60×60

72000/3600

20meter/s

v²=u²+2as

(20)²=(0)²+ 2×a×40m

400=80a

400/80=a

a=5m/s².

(ii) Final Velocity(v)=20m/s

Acceleration (a)=5m/s²

Initial velocity (u)=0m/s

Time. (t)=?

v=u+at.

20=0+5a

20/5=a

a=4second