# HESI Physics Practice Test 2

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#### A baseball weighs 0.145 kg. It needs to be thrown at what speed to have a kinetic energy of 57 J?

Correct! Wrong!

Explanation:
Substituting the given values into the formula:
57 J = 0.5 * 0.145 kg * velocity^2
To find the velocity, we can rearrange the equation and solve for velocity:
velocity^2 = (57 J) / (0.5 * 0.145 kg)
velocity^2 = 786.20689655 m^2/s^2
Taking the square root of both sides:
velocity = √(786.20689655 m^2/s^2)
velocity ≈ 28.0 m/s

#### Which of the following is true regarding the way light travels?

Correct! Wrong!

Explanation:
Light is a curiosity in that it acts as both a wave and a particle. It only changes direction via reflection (bouncing off of something) or refraction (passing from one medium to another). In a vacuum, the speed of light is constant, but when passing through a medium that has an index of refraction different from a vacuum, light’s speed slows.

#### The rate at which a vehicle's velocity changes over time?

Correct! Wrong!

Explanation:
Acceleration is the rate of change in velocity over a period of time.

#### At a speed of 8 m/s, a 0.5 kg object suspended from a 0.75 m rope circles a center point. How much stress does the string feel in the absence of gravity?

Correct! Wrong!

Explanation:
Given:
Mass of the object (m) = 0.5 kg
Velocity (v) = 8 m/s
Substituting the given values into the formula:
F = (0.5 kg) × (8 m/s)^2 / (0.75 m)
F = 0.5 kg × 64 m^2/s^2 / 0.75 m
F = 32 kg·m/s^2 / 0.75 m
F ≈ 42.7 N

#### Which of the following is true of a negatively charged particle?

Correct! Wrong!

A negatively charged particle has more electrons (which have negative charge) than protons (which have a postive charge).

#### It is possible for an object to show two different types of motion at the same time.

Correct! Wrong!

Explanation:
In Project Motion it is possible for an object to display two types of motion simultaneously.

#### A fresh egg will float in water…

Correct! Wrong!

Eggs are typically more dense than water, which makes them sink. However, if enough salt is added to the water, the water becomes more dense than the egg, which will cause it to float.

#### A subatomic particle is which of the following in relation to an atom?

Correct! Wrong!

Subatomic particles- which include neutrons, protons, and electrons- are much smaller than atoms.

#### Who discovered the special theory of relativity?

Correct! Wrong!

The Theory of Relativity is one of physics’ most famous and was proposed by Albert Einstein.

#### A push or a pull on an item is defined as _________.

Correct! Wrong!

Explanation:
Force is defined as a push or a pull on an object.

#### How fast does sound travel through a vacuum?

Correct! Wrong!

The speed of sound in a vacuum is 0 m/s because sound waves cannot travel through a vacuum.

#### According to the theory of the same name, after the “Big Bang” there were only what two things?

Correct! Wrong!

Explanation:
The Big Bang Theory attempts to explain the origins of the universe. According to the theory, a “big bang” produced matter and antimatter in equal quantities.

#### What planet is the slowest rotating and often referred to as Earth’s “sister planet?”

Correct! Wrong!

Venus is the slowest-rotating planet and is sometimes referred to as Earth’s “sister” because of their similar size and distance from the sun.

#### Unless operated on by an imbalanced force, the body at rest will remain at rest, and the body in motion will remain in motion with a constant velocity; F=ka

Correct! Wrong!

Explanation:
Newton's First Law of Motion states that the body at rest will remain at rest, and the body in motion will remain in motion with a constant velocity, unless acted on by an unbalanced force; F=ka.

#### A ball is at the top of a hill. Which factor, or factors, is responsible for its potential energy?

Correct! Wrong!

A ball on a hill would have potential (or stored) energy because of its location on the top of a hill and because of its mass. Recall that gravitational potential energy is the product of an object’s mass, position, and the acceleration due to gravity.

#### A woman has a mass of 50 kg on the moon. What is her mass on Earth?

Correct! Wrong!

While the woman’s weight would change due to differences in gravitation force, her mass would remain the same no matter if she was on the Earth or moon.