Physics NCFE Released (16-17)

A 3,150-kg truck accelerates from 4.2 m/s to 7.8 m/s in 14 s. Which describes the average force needed for the truck to accelerate under these conditions?

• 810 N

• 950 N

• 1,800 N

• 2,700 N

A 45-kg boy throws a 0.50-kg ball at 15 m/s. Then, a 60-kg boy throws the same ball at 15 m/s. Which boy generates more momentum?

• Neither boy generates any momentum.

• The 45-kg boy generates more momentum.

• The 60-kg boy generates more momentum.

• Both boys generate the same amount of momentum.

A machine pushes a 400.0-N box forward with a horizontal force of 50.0 N for 10.0 s. By how much does the momentum of the box change due to the machine? (Ignore friction.)

• 4.50 × 10³ N • s

• 4.00 × 10³ N • s

• 3.50 × 10³ N • s

• 5.00 × 10² N • s

Which graph represents the relationship between the gravitational potential energy and the height of an object relative to the ground?

• 
• 
• 
• 

A circuit consists of a single resistor, R1, and a 9-V battery. A second identical resistor, R2, is added to the circuit in parallel with R1. How does the potential difference across R1 change after R2 is added?

• The potential difference decreases because a 9-V battery cannot handle resistors in parallel.

• The potential difference decreases because two resistors in parallel can split the 9 V equally.

• The potential difference remains the same because resistors in parallel do not cause a change in voltage.

• The potential difference remains the same because resistors in parallel create extra current that balances the extra resistance.

Two rocks with masses of 5 kg and 10 kg are dropped from a height of 20 m above the ground. Just before they reach the ground, which statement is true about the rocks? (Ignore all friction.)

• The value for the acceleration of the 5-kg rock is the same as the value for the 10-kg rock, but the velocity values are different.

• The values for the acceleration and velocity of the 5-kg rock are the same as the values for the 10-kg rock.

• The values for the acceleration and velocity of the 5-kg rock are less than the values for the 10-kg rock

• The values for the acceleration and velocity of the 5-kg rock are greater than the values for the 10-kg rock

The atoms of both copper and rubber contain protons and electrons; however, copper is more conductive than rubber. Why is copper able to conduct more electricity?

• Copper contains free electrons, and rubber contains bound electrons

• Rubber contains free electrons, and copper contains bound electrons

• Copper contains free protons, and rubber contains bound protons

• Rubber contains free protons, and copper contains bound protons

A positive glass rod is placed near a neutral metallic sphere. If they do not touch, what happens to the charges inside the sphere?

• Like charges attract, which causes the sphere to become polarized

• Unlike charges attract, which causes the sphere to become polarized

• Like charges attract, which causes the sphere to become charged

• Unlike charges attract, which causes the sphere to become charged

An electron loses 2.00 x 10-15 J of energy traveling to the screen of a laptop computer. Why is the energy loss small?

• because the charge is small

• because the charge is large

• because the resistance is small

• because the resistance is large

How does a large number of turns in an electromagnet create a strong magnetic field?

• Each turn increases the amount of time it takes for the current to travel through the wire.

• Each turn decreases the amount of time it takes for the current to travel through the wire

• Each turn increases the amount of induction produced by the current in the wire.

• Each turn decreases the amount of induction produced by the current in the wire