PHYSICS- STAAR PREP 2 20 PRACTICE QUESITONS

Question 1 Two electrically charged, hollow aluminum spheres of the same mass, size

and charge are pictured below. If both are on a hard, flat table in close proximity to each other what is the most probable result?

a. Both spheres will roll towards each other at the same initial rate of acceleration, and as they get closer to each other the acceleration will increase.

b. Both spheres will roll away from each other at the same initial rate of acceleration, and as they get further apart the acceleration will decrease.

c. Both spheres will roll away from each other at the same rate of acceleration, and as they get further apart the acceleration will continue at the same rate.

d. Both spheres will roll towards each other at the same initial rate of acceleration, and as they get closer to each other the acceleration will continue at the same rate.

Negative Charge of 1 Negative Charge of 1Sphere 1 Sphere 2

Answer 1

b. Both spheres will roll away from each other at the same initial rate of acceleration, and as they get further apart the acceleration will decrease.

Question 2 Two unlike electrically charged particles are located a

certain distance away from each other. If the distance between the two is reduced by half, what will happen to the forces between the two particles?

a. the two particles will attract, and the forces of attraction will quadruple.

b.The two particles will attract, and the forces of attraction will double.

c.The two particles will repel, and the forces of repulsion will quadruple.

d.The two particles will repel, and the forces of repulsion will double.

Answer 2

a. the two particles will attract, and the forces of attraction will quadruple.

Question 3

A force can exist between two objects without those objects being in contact. What force is at work when a ball tossed into the air falls back to Earth?

a. gravitational force b. buoyant force

c. electrical force d. magnetic force

Answer 3

a. gravitational force

Question 4

The gravitational force between objects depends upon several factors. How would the gravitational attraction between two objects change if the mass of one of the objects decreased?

a. The gravitational attraction would not change.

b.The gravitational attraction would increase.

c.The gravitational attraction would decrease at first, then increase.

d.The gravitational attraction would decrease.

Answer 4

d. The gravitational attraction would

decrease

Question 5

How would the gravitational force change if the distance between the objects increased?

a.The force would fluctuate randomly.

b.The force would increase.

c.The force would decrease.

d.The force would not change.

Answer 5

c. The force would decrease

Question 6

From which planet shown in the table would an object have to move farthest to become weightless?

a.Mercury B. Earth c.Venus D. Mars

Planet Mass

Mercury 3.302 x 1023

Venus 4.869 x 1024

Earth 5.974 x 1024

Mars 6.419 x 1023

Answer 6

B. Earth - has the largest mass

Question 7

Which planet shown in the table would have the least gravitational attraction for an object on its surface?

a.Venus B. Mercury c.Mars D. Earth

Planet MassMercury 3.302 x 1023

Venus 4.869 x 1024

Earth 5.974 x 1024

Mars 6.419 x 1023

Answer 7

B. Mercury

Question 8

The picture below shows three electrically charged particles. The center particle is equidistance away from the outer two particles. Which diagram most accurately depicts the relative electromagnetic forces resulting from the amount of charge on each particle?

______________________________________

1 Negative 3 Negative3 Positive

1 Negative 3 Negative3 Positive

1 Negative 3 Negative3 Positive

1 Negative 3 Negative3 Positive

Answer 8

1 Negative 3 Negative3 Positive

Question 9

Two electrically charged particles are moved closer to each other. Attractive forces between the particles are detected to be getting stronger and stronger as the particles move closer together. What can be determined about the two particles?

a. The particles are of like charge. b.T he particles are of unlike charge. c. The particles are rotating around each other as

in an orbit. d. The two particles are both electrons.

Answer 9

b. T he particles are of unlike charge.

Question 10

How would the gravitational force change if the objects moved closer together?

a. The force would not change. b.The force would decrease. c.The force would fluctuate randomly. d.The force would increase.

Answer 10

d.The force would increase.

How would the gravitational attraction between two objects change if the mass of both objects increased?

a.The gravitational attraction would increase. b.The gravitational attraction would not

change. c.The gravitational attraction would

decrease. d.The gravitational attraction would increase

at first, then decrease.

Answer 11

a.The gravitational attraction would increase.

Question 12

What would occur between the spheres below?

a.Both spheres will have a net force of zero on them, and will not move.

b.Both spheres will have forces attracting each other and will roll towards each other.

c.Both spheres will have forces opposing each other and will roll away from each other.

d.Both spheres will have a net force directed towards the right and will both move to the right.

Net Positive Charge Net Positive Charge

Answer 12

c.Both spheres will have forces opposing each other and will roll away from each other.

Question 13

Which change would increase the total current, I, flowing through this circuit?

A increasing the voltage of the battery

B decreasing the length of the wires  C rewiring the two resistors in a series  D adding a third resistor in parallel 

Answer 13

D adding a third resistor in parallel

Question 14

Calculate the total resistance of the following circuit.

Answer 14

4.8 ohms

Question 15

What is the total current in the circuit?

Answer 15

5 amps

Question 16

In order to make a stronger electromagnet, which one of the following is effective?

A use more turns (wraps) of wire

B use an iron core instead of a wooden core

C use more current through the wire  D All of the above are correct.

Answer 16

D –all of the above

Question 17

A 12.0 volt battery is connected to 4 identical 3.00 ohm resistors connected in parallel to each other. What is the current in the circuit?

 

Answer 17

16 amps

Question 18

In the water flow analogy, the current in a circuit is analogous (same as) to —

A the water pipes.  B the water pump.

C the on/off valve.  D the water.

Answer 18

D -The water

Question 19

Two electrically charged particles are moved closer to each other. Repelling forces between the particles are detected to be getting stronger and stronger as the particles move closer together. What can be determined about the two particles?

a.The particles are of like charge. b.The particles are of unlike charge. c.The particles are rotating around each other as in an orbit. d.The two particles are an electron and a proton.

Answer 19

a. The particles are of like charge.

Question 20

Angie weighs 380 Newtons. She is carrying a 25.6-newton backpack. She climbs the stairs in her school from the first floor to the second floor, a height of 2.9 meters. How much work, in joules, has Angie done?

Answer 20

1176 joules

Question 21

A ball is thrown down at a speed of 3.0 m/s and accelerates under the pull of gravity for 2.0 seconds. How fast is it moving?

A. 6 m/s B. 23 m/s C. 18m/s D. 6m

Answer 21

B. 23 m/s

Question 22

A rubber ball strikes the ground with a downward force of 12 N. According to Newton’s third law, how much force does the ground exert on the ball?

Answer 22

12 N Upward

Question 23

A metal ball has a momentum of 12 kg.m/s southward. If the ball has a velocity of 3m/s, what is the mass?

Answer 23

4 kg

Question 24

A dart with a mass of 50 g is thrown at 15 m/s and sticks into a 100 g apple hanging on a string. What is the velocity of the dart and apple just after the dart is embedded?

Answer 24

5 m/s

Question 25

Air bags help to minimize injuries by providing a large area for the force of impact to be exerted. In terms of the impulse-momentum theory, what is another advantage of an air bag?

A. decreases the momentum of the passenger B. Increases the amount of time the force is

applied C. Decreases the net force applied by the air bag D Increases the impulsive force applied to the

passenger

Answer 25

B. Increases the amount of time the force is applied