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1. Which of the following energy transformations best describes the operation of a solar powered battery charger?

(a) electrical energy --> thermal energy --> kinetic energy
(b) nuclear energy --> potential energy --> chemical energy
(c) thermal energy --> elastic potential energy --> electrical energy
(d) radiant energy --> electrical energy --> chemical potential energy
(e) radiant energy --> thermal energy --> electrical energy
my answer: e

2. A jet engine applies a thrust force of 21.0 N vertically to a 0.500 kg rocket. The force of air friction is negligible for the first 50.0 cm of flight. Find the kinetic energy gained by the rocket in the first 50.0 cm of takeoff.
(a) 4.0 J
(b) 8.05 J
(c) 10.5 J
(d) 21 J
(e) 32 J
my answer: c

3. A 300 N force is applied horizontally to a 50kg crate, originally at rest, pushing it 2 m. The force of friction between the crate and the floor is 200 N. The final kinetic energy of the crate is:
a)0 J
b)200 J
c)400 J
d)600 J
e)300000 J
my answer: i think it is d

4. If a 1000 kg car accelerates from 10 m/s to 20 mIs, the amount of work done is:
(a) 112500 J
(b) 10000 J
(c) 150000 J
(d) 5000 J
(e) O J
my answer: c

5. The rated power output of an engine is 10 hp, 7460 W. How much energy would it produce in 10 minutes?
(a) 0 J
(b)100 J
(c) 74600 J
(d) 4.5 MJ
(e) 746 MJ
my answer: not sure

6. An electrical hair dryer consumes 90 kJ in one minute. What is the power used by this hair dryer?
(a) 90 W
(b)100W
(c) 1500 W
(d) 5.4 kW
my answer: a

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3 answers
  1. you got number 4 correct. Others wrong

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    bobpursley
  2. i think the first one is D
    2 and 4 are correct
    i think 3 may be c but im not sure

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  3. 2 is technically correct but you forgot to include the gravity so its actually b

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