# Physics exam | Physics homework help

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- Question 1
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- How many significant figures are in 1.609?
- Select one:
- a. 3
- b. 4
- c. 2
- d. 1
- Question 2
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- How many significant figures are in .00254?
- Select one:
- a. 5
- b. 3
- c. 6
- d. 2
- Question 3
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- Which is greater, an acceleration from 25 km/h to 30 km/h or one from 96 km/h to 100 km/h if both occur during the same time?
- Select one:
- a. 25 km/h to 30 km/h
- b. 96 km/h to 100 km/h
- c. Same acceleration for both.
- d. Not enough information
- Question 4
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- Light travels in a straight line at a constant speed (constant velocity) of 300,000 km/s. What is the acceleration of light?
- Select one:
- a. 0
- b. 300,000 km/s
- c. Not enough information.
- d. 9.8 m/s^2
- Question 5
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- John and Tracy look from their 80.-m high-rise balcony to a swimming pool below-not exactly below, but rather 12 m out from the bottom of their building. They wonder how fast they would have jump horizontally to succeed in reaching the pool. What is the answer?
- Select one:
- a. 5 m/s
- b. 80 m/s
- c. 20 m/s
- d. 3.0 m/s
- Question 6
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- A ball is thrown horizontally from a cliff at a speed of 10 m/s. What is its speed two second later. Note: Find the vertical component of the velocity after 2 second by using v (vertical component) = gt and since there is no horizontal acceleration, the horizontal velocity does not change and is equal to 10 m/s. Now find the speed (magnitude of the resultant velocity) with the use of Pythogorean theorem. That is V = SQRT [(v-(vertical component))^2 + (v-(horizontal component))^2].
- Select one:
- a. 14 m/s
- b. 22 m/s
- c. 10 m/s
- d. 19.8 m/s
- Question 7
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- What is the acceleration of a 40-kg block of cement when pulled sideways with a net force of 200 N?
- Select one:
- a. 0.2 m/s^2
- b. 5 m/s^2.
- c. 8000 m/s^2.
- d. 0
- Question 8
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- If a mass of 1 kg is accelerated 1 m/s^2 by a force of 1 N, what would be the acceleration of 2 kg acted on by a force of 4 N?
- Select one:
- a. 2 m/s^2.
- b. 4 m/s^2.
- c. 0
- d. 1 m/s^2.
- Question 9
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- What is the acceleration of a 25-kg block of cement when pulled sideways with a net force of 200 N?
- Select one:
- a. 0.2 m/s^2
- b. 5 m/s^2.
- c. 8000 m/s^2.
- d. 8 m/s^2
- Question 10
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- How many joules of kinetic energy does a 1-kg book have when it is tossed across the room at a speed of 2 m/s?
- Select one:
- a. 2 J
- b. 4 J
- c. 0 J
- d. 0.5 J
- Question 11
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- This question is typical on some driver’s license exams: A car moving at 50 km/h skids 15 m with locked brakes. How far will the car skid with the locked brakes at 150 km/h?
- Select one:
- a. 45 m
- b. 135 m
- c. 15 m
- d. 150 m
- Question 12
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- Why is it incorrect to say that impulse equals momentum?
- Select one:
- a. Impulse = momentum x force
- b. Impulse = momentum x time
- c. Impulse is equal to change in momentum
- d. It is the same.
- Question 13
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- Lillian (mass 40 kg) standing on slippery ice catches her leaping dog (mass 15 kg) moving horizontally at 3.0 m/s. What is the speed of Lillian and her dog after the catch?
- Select one:
- a. 3 m/s
- b. 0.82 m/s
- c. 0 m/s
- d. 9 m/s
- Question 14
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- A lady bug sits halfway between the axis and the edge of a phonograph record. What will happen to its tangential speed if the RPM is doubled? At this doubled rate, what will happen to its tangential speed if it crawls out to the edge?
- Select one:
- a. (a) no change, (b) no change
- b. (a) doubled, (b) four times the original value in first part.
- c. (a) doubled, (b) doubled,
- d. (a) half the value, (b) one fourth the original value
- Question 15
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- What is the tangential speed of a passenger on a Ferris wheel that has a radius of 10 m and rotate once in 30 s?
- Select one:
- a. 0.33 m/s
- b. 10 m/s
- c. 300 m/s
- d. 2 m/s
- Question 16
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- Consider a bicycle that has wheels with a circumference of 2 m. What is the linear speed of the bicycle when the wheels rotate at 1 revolution per second?
- Select one:
- a. 1 m/s
- b. 2 m/s
- c. 3 m/s
- d. 4 m/s
- Question 17
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- What is the tangential speed of a passenger on a Ferris wheel that has a radius of 10 m and rotate once in 20 s?
- Select one:
- a. 3 m/s
- b. 10 m/s
- c. 20 m/s;
- d. 2 m/s
- Question 18
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- A 10,000 N vehicle is stalled one-quarter the way across the bridge. Calculate the additional reaction forces that are supplied at the supports on both ends of the bridge. Note: Both forces at the end will be vertically upwards.
- Select one:
- a. 5000 N at both ends
- b. 7500 N at right end and 2500 N at left end
- c. 7500 N at the left end and 2500 N at the right end
- d. 10,000 N at both ends
- Question 19
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- To tighten a bolt, you push with a force of 80 N at the end of a wrench handle that is 0.25 m from the axis of the bolt. (a) What torque are you exerting? (b) If you move your hand inward to be only 0.10 m from the bolt, what force do you have to exert to achieve the same torque?
- Select one:
- a. (a) 20 N.m, and (b) 200 N
- b. (a) 20 N.m, and (b) 80 N
- c. (a) 320 N.m, and (b) 200 N
- d. (a) 80 N.m, and (b) 80 N
- Question 20
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- Which has more volume – a kilogram of gold or a kilogram of aluminum?
- Select one:
- a. a kilogram of gold has more volume
- b. a kilogram of aluminum gas more volume
- c. same volume for both
- d. not enough information
- Question 21
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- A rectangular barge, 5 m long and 2 m wide, floats in fresh water. (a) find how much deeper it floats when its load is 400-kg horse. (b) If the barge can only be pushed 15 cm deeper into the water before water overflows to sink it, how many 400-kg horses can it carry? Note that buoyant force = volume displaced x density of water x g, where density of water is 1000 kg/m^3 and g = 10 m/s^2. Also 400 kg load is 400 g = 4000 N.
- Select one:
- a. .04 m or 4 cm and 3 horses only
- b. .15 m or 15 cm and only 1 horse
- c. .01 m or 10 cm and only 1 horse
- d. .01 m or 1 cm and 15 horses
- Question 22
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- What is the mass of a cubic meter of air at room temperature (20 deg. C)? Note that the density of air at room temperature (20 deg. C) is 1.21 kg/m^3.
- Select one:
- a. 20 kg
- b. 1.21 kg
- c. 10 kg
- d. 0.1 kg