Q: A 2 kg object is moving at 3 m/s. What is its kinetic energy?

$$KE = \frac{1}{2} \times 2 \times 3^2$ = 9 J$$

Q: A wave has a frequency of $$500 Hz $$and a wavelength of $$0.6 m. $$What is its speed?

$$v = 500 \times 0.6 = 300 m/s$$

Q: A block is lifted to a height of $$2 m$$, gaining $$40 J of $$potential energy. What is the mass of the block? (Use $$g = 10 m/s$^2)$$

$$m = \frac{40}{2 \times 10} = 2 kg$$

Question 1

A car accelerates from rest under a constant force. Which of Newton's laws best explains the relationship between the force applied and the car's acceleration?

Accepted Answer

Newton's Second Law: The acceleration of an object is proportional to the net force and inversely proportional to its mass, $$F = ma.$$

Question 2

A student pushes a box across a horizontal floor with a force of 50 N. The box moves at a constant velocity. What is the magnitude of the frictional force acting on the box?

Accepted Answer

$$50 N$$

Question 3

Which of the following best describes the energy transformation in a hydroelectric power plant?

Accepted Answer

Gravitational potential energy to kinetic energy to electrical energy

Question 4

A ball is dropped from a height $$h$$ and falls freely under gravity. Which equation gives the velocity of the ball just before it hits the ground?

Accepted Answer

$$v = \sqrt{2gh}$$

Question 5

A 2 kg object is moving at 3 m/s. What is its kinetic energy?

Accepted Answer

$$KE = \frac{1}{2} 	imes 2 	imes 3^2$ = 9 J$$

Question 6

Which of the following statements about electric current is correct?

Accepted Answer

Electric current is the rate at which charge flows through a conductor, $$I = \frac{Q}{t}.$$

Question 7

A resistor has a resistance of $$10\ \Omega$$ and a voltage of $$5 V is $$applied across it. What is the current through the resistor?

Accepted Answer

$$I = \frac{5}{10} = 0.5 A$$

Question 8

Which of the following best explains why sound travels faster in solids than in gases?

Accepted Answer

Particles in solids are closer together, allowing vibrations to transfer more efficiently.

Question 9

A student connects two resistors, $$R_1 = 4$$\ \Omega$$ and R_2$ = 6\ \Omega$$, in series. What is the total resistance?

Accepted Answer

$$R_{total} = 4 + 6 = 10\ \Omega$$

Question 10

Which of the following is a correct statement of the law of conservation of energy?

Accepted Answer

Energy can be transformed from one form to another, but the total energy of an isolated system remains constant.

Question 11

A wave has a frequency of $$500 Hz $$and a wavelength of $$0.6 m. $$What is its speed?

Accepted Answer

$$v = 500 	imes 0.6 = 300 m/s$$

Question 12

A block is lifted to a height of $$2 m$$, gaining $$40 J of $$potential energy. What is the mass of the block? (Use $$g = 10 m/s$^2)$$

Accepted Answer

$$m = \frac{40}{2 	imes 10} = 2 kg$$

Question 13

Which of the following best describes the function of a capacitor in an electric circuit?

Accepted Answer

It stores electrical energy in the form of an electric field.

Question 14

A student observes that when the separation between two charged particles is doubled, the force between them changes. Which equation describes this relationship?

Accepted Answer

$$F = k \frac{q_1$ q_2$}{r^2$}$$; the force is reduced to one-fourth.

Question 15

Which of the following is a real-world example of Newton's Third Law?

Accepted Answer

A swimmer pushes water backward and moves forward.

Question 16

A circuit contains a $$12 V $$battery and two resistors, $$R_1 = 3$$\ \Omega$$ and R_2$ = 6\ \Omega$$, in parallel. What is the total current supplied by the battery?

Accepted Answer

$$I = \frac{12}{3} + \frac{12}{6} = 4 + 2 = 6 A$$

Question 17

Which of the following best describes the difference between heat and temperature?

Accepted Answer

Heat is the energy transferred due to a temperature difference; temperature is a measure of the average kinetic energy of particles.

Question 18

A pendulum swings back and forth. At its highest point, which type of energy is maximized?

Accepted Answer

Gravitational potential energy

Question 19

A student wants to determine the acceleration of a cart rolling down an inclined plane. Which method would provide the most accurate measurement?

Accepted Answer

Use a stopwatch to measure the time taken for the cart to travel a known distance and apply $$a = \frac{2d}{t^2$}.$$

Elements of Physics – Course Syllabus and Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard