Chapter 3 Science
One kilowatt (kW) is the same as ___ watts (W).
1000
A kilowatt is equal to ______.
1000 W
A car's mass is 1000 kg and is moving at 20m/sec. What is the car's kinetic energy? KE = 1/2 (mass) (velocity)
200,000 J
Calculate the potential energy of a 100 kg air conditioner sitting in a window 3000 m in the air. Hint: PE = m X g X h
294,000 J
What is the power output of a 40 kg person running up a flight of stairs 4 m high in 4 s? Hint:
392W
Calculate the work done when pushing a box 450 m with 10N of force. W = f X d
4500
A total of 4900 J is used to lift a 50 jg mass. What height is the mass raised to? Hint: W = m X g X h
4900 = (50)(9.8)(h) h = 10
Calculate the work done when pushing on a 500 kg boulder and moving it 0 meters. Hint: W = f X d
500
Calculate the work done in lifting a 30 kg object to a height of 20 meters. Hint: W = m X g X H
5880J
Calculate the work a 300 W electric grinder can do in 5 minutes. Hint: P = w/t
60
Calculate the work and power done in holding a 50 kg object of 2 meters above the floor for 10 seconds. Hint: W = m X g X h P = w/t
980 J 98
Which of the following is true according to the law of conservation of energy?
A certain quantity keeps the same value it originally had no matter what changes the system undergoes.
Which of the following is a good example of spin stabilization and the conservation of angular momentum?
A planet's speed when spinning in orbit around the sun is greatest when close to the sun and least when far away. A top doesn't topple while spinning. Footballs spin and don't tumble in flight.
Who is credited with the theory of relativity?
Albert Einstein
What is the primary purpose of having the first set of fuel tanks and the associated motor cast off from a multistage rocket after the fuel has been used for liftoff and to carry the rocket high in the atmosphere?
Based on conservation of linear momentum, when the second stage fires, the rocket is already moving rapidly and does not need to carry the weight.
___ momentum reflects the tendency of a spinning body to continue to spin.
Blank 1: Angular
Less than two centuries ago, most scientists regarded heat as an actual substance called ___.
Blank 1: caloric
A(n) ___ law applies to a system of any kind and states that a certain quantity keeps the same value it originally had, no matter what changes the system undergoes.
Blank 1: conservation
The ability to do work is known as ___.
Blank 1: energy
Work is done by a ___ acting on an object and is equal to the magnitude of the force multiplied by the ___ through which the force acts when both are in the same direction.
Blank 1: force Blank 2: distance
The energy due to motion is known as ___ energy.
Blank 1: kinetic or KE
A moving object tends to continue moving at constant speed along a straight path. This tendency is known as the object's ___ momentum.
Blank 1: linear
Mass multiplied by velocity equals momentum.
Blank 1: linear
A simple machine is a device that increases the force; whatever is exerting the input force must move through a ___ distance than the distance through which the load moves.
Blank 1: longer, larger, or greater
The ___ advantage of any machine is the ratio between the output and input force.
Blank 1: mechanical
The energy of an object due to its position is called ___ energy.
Blank 1: potential or PE
Work divided by time equals ___.
Blank 1: power
Which of the statements below are part of the law of conservation of energy?
Energy can be converted from one form to another, but the total energy remains constant. Energy is never created or destroyed.
Select the statement below that best describes how energy can be transformed or converted.
Energy can be transferred back and forth between kinetic and potential energy.
Which of the statements below are part of the law of conservation of energy?
Energy is never created or destroyed. Energy can be converted from one form to another, but the total energy remains constant.
True or false: Energy cannot be converted from kinetic to potential energy.
False
Which of the following is a good example of spin stabilization and the conservation of angular momentum?
Footballs spin and don't tumble in flight. A planet's speed when spinning in orbit around the sun is greatest when close to the sun and least when far away. A top doesn't topple while spinning.
Select all the formulas below that can be used to determine the mechanical advantage (MA).
MA = resistance force (or Fout)/effort force (or Fin) MA = input distance/output distance
Which of the following statements is true in regard to matter supplying energy?
Matter can be moving or at rest.
___ rockets are used in the exploration of space and involve sections that ignite, burn fuel, and cast off empty tanks in sequence so as to maintain linear momentum and allow the rocket to reach a higher final speed than would otherwise be possible.
Multistage
What happens to starlight as it passes near the sun?
Starlight is deflected due to the sun's strong gravitational pull.
Which of the following are postulates of relativity?
The speed of light in free space has the same value for all observers. The laws of physics are the same in all frames of reference moving at constant velocity with respect to one another.
What do all the following have in common? (1) A stationary top falls over at once but a spinning top stays upright; (2) a spinning football doesn't tumble during flight; (3) a rifle bullet that spins and maintains its direction for a longer range. (Select all that apply.)
They are all demonstrations of the conservation of angular momentum. They are all demonstrations of spin stabilization.
Which of the following is the equation for the conservation of momentum?
Total momentum = m1v1 = (m1 + m2) v2
Which formula below defines work?
Work = force x distance (W = Fd)
Energy is defined as the ______.
ability to do work
The term caloric is described as ______.
an actual substance that flows from hotter to colder bodies as heat
The concept of momentum refers to the ______.
behavior of moving objects
Gravity has the ability to ______ light.
bend
The mechanical advantage can be determined by ______ resistance force (Fout) by the effort force (Fin) or the input distance by the output distance.
dividing
Matter does not need to be moving to supply energy because matter contains ______.
energy
The law of conservation of energy states that ______.
energy is never created or destroyed. However, it can be converted between different forms of energy with the total remaining constant
Mass multiplied by velocity equals ___ momentum.
linear
The ______ of an object describes how it tends to continue moving at constant speed along a straight path.
linear momentum
Linear momentum equals ______.
mass multiplied by velocity
The force or distance advantage you gain by using a machine is called the ______ advantage.
mechanical
In the absence of outside forces, the total momentum of a set of objects remains the same no matter how the objects interact with one another. This statement is called the law of conservation of ______.
momentum
Moving objects are said to have ______.
momentum
The equation for the conservation of ___ is m1v1 = (m1 + m2) v2.
momentum
Kinetic energy is defined as the energy of ______.
motion
Potential energy is the energy due to ______.
position
"The laws of physics are the same in all frames of reference moving at constant velocity with respect to one another," and "the speed of light in free space has the same value for all observers" are both postulates of ___.
relativity
The law of conservation of momentum states that in the absence of outside forces, the total momentum of a set of objects ______.
remains the same no matter how the objects interact with one another
A simple machine aids in getting work done by allowing a ______.
small force to be applied over a large distance to get a large force working over a smaller distance
The theory of relativity links time and ___, but also energy and matter.
space
Angular momentum is ______.
the tendency of a spinning body to continue to spin
Power is ______.
work divided by time
