Page 11 - TRIAL 2

A. P
B. Q
C. R
D. S

8. An arrow is fired, via a bow, straight up. It rises
find the work done in pulling the box to the top for a while and then drops back to the ground.
of the plane The process, taking the arrow from loading to
A. 1750 J just prior to touch down, can best be described
B. 2452.5 J by a series of energy transformations
C. 1250.5 J corresponding to
D. 1500 J A. work, elastic-PE, KE, gravitational-PE,
KE
5. A car moving in a straight line with a constant B. work, KE, elastic-PE, KE
velocity has kinetic energy E. If the velocity of C. KE, gravitational-PE, work
the car is doubled, its new kinetic energy will D. elastic-PE, gravitational-PE, KE
be. E. none of the above
A. 2E
B. 4E 9. A lizard of mass 2 kg climbed a tree from the
C. 6E ground to a height of 5 m in 25s. Find the
D. 8E power of the lizard in this action.
A. 100 W
6. The figure shows a ball is thrown from a B. 5.7 W
building of height 10m. Find the velocity of the C. 3.924 W
ball right before it hit the ground. D. 50.26 W

10. Abu with a mass of 70 kg climbs a coconut tree
to a height of 6m to pick a coconut in 1 minute.

What is his power?
A. 4.87 W

B. 68.67 W
C. 250.76 W
D. 359.64 W
-1
A. 10 ms
-1
B. 14.87 ms 11. An electric motor is used to lift a mass of 120
-1
C. 5.8 ms kg. The power of the motor is 1200 W. If the
-1
D. 20 ms motor is 60% efficient, calculate the time taken
to lift the mass through a height of 4.2m.
7. An object is thrown in the direction as shown in
A. 6.9 s
diagram.
Q R B. 11.9 s
P C. 5 s
D. 15 s

12. A pile driver can lift a pile head of mass 200 kg

to a height of 10 m in 20s. During this time,
S
At which point of the path does the stone possess 40kJ of electrical energy is supplied to the pile
minimum kinetic energy? driver. Find the efficiency of the motor.

10