1. Speed, Momentum, Acceleration, Work, Power, and Potential Energy Practice Problems TEK I6A – describe the law of conservation of energy; and TEK I4A – calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines

2. 1. A mechanic used a hydraulic lift to raise a
12,054 N car 1.89 m above the floor of a
garage. It took 4.75 s to raise the car. What
was the power output of the lift?
A 489W
B 1815W
C 4796
D 30,294W
P=W/t
W=Fd
W=(12,054N)(1.89m)=22,782.06J
P=(22,782.06J)/(4.75s)=4,796.2W
Answer:C
(Practice problem from TEA released TAKS Test)

3. 2. The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately how much work did she do in raising the barbell?
F 380 J
G 982 J
H 2,000 J
J 10,000 J
W=Fd
W=(980N)(2.04m)=1999.2J
Answer: H
(Practice problem from TEA released TAKS Test)

4. 3. According to this graph, what was the bicycle’s acceleration between 6 and 10 seconds?
A 0.0m/s2
B 0.65m/s2
C 1.6m/s2
D 6.5m/s2
Answer: A
(Practice problem from TEA released TAKS Test)

5. 4. An ant crawled from Point A to Point B in 4. 0 seconds
4. An ant crawled from Point A to Point B in 4.0 seconds. To the nearest tenth, what was the ant’s speed in centimeters per second? Record and bubble in your answer on the answer document.
V=d/t
On the actual TAKS test the students would need to use the ruler on their formula chart to find the distance.
(Practice problem from TEA released TAKS Test)

6. 5. A car traveled 150 km in 2. 5 hours
5. A car traveled 150 km in 2.5 hours. What was its average speed in km per hour? Record and bubble in your answer on the answer document.
V=d/t
V=(150km)/(2.5hrs)=60km/hr
Answer: 60 or 60.0 or or would all be counted correct!
(Practice problem from TEA released TAKS Test)

7. 6. A ball moving at 30 m/s has a momentum of 15 kg·m/s
6. A ball moving at 30 m/s has a momentum of 15 kg·m/s. The mass of the ball is —
A 45 kg
B 15 kg
C 2.0 kg
D 0.5 kg
p=mv
(15kg•m/s)=m(30m/s)
m=(15kg•m/s)/(30m/s)=0.5kg
Answer: D
(Practice problem from TEA released TAKS Test)

8. 7. How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N?
A 300J
B 750J
C 1,000J
D 15,000J
W=Fd
W=(20N)(15m)=300J
Answer: A
(Practice problem from TEA released TAKS Test)

9. 8. What is the potential energy of the rock? A 59,900 joules
B 64,600 joules
C 93, 100 joules
D 121,600 joules
PE=mgh
PE=(95kg)(9.8m/s2)(100m)=93,100joules
Answer: C
(Practice problem from TEA released TAKS Test)