Definitions
Define Scalar and Vector
A quantity that only has a magnitude. A quantity that has both magnitude and direction.
Which star is closest to the Earth?
The Sun.
The next closest star would be Proxima Centauri in the Alpha Centauri solar system that is actually a triple star system.
Describe where the centripetal acceleration and the tangential speed vectors are pointing in circular motion.
Centripetal acceleration points into the center of the circle. The tangential speed points tangent to any point on the circle and towards where the object's inertia would be carrying it. The speed and acceleration vectors in circular motion are perpendicular to each other.
True or False
An object moving at constant speed must also have constant acceleration.
True, an object moving with a constant (unchanging) speed has a constant acceleration of 0 m/s/s
_____________ is the tendency of an object to keep moving or stay at rest.
Inertia (directly related to mass of the object)
List and define Newton's Three Laws
1 - Law of Inertia
2 - F=ma
3 - Equal and opposite reaction
What is the smallest country on Earth?
Vatican City
What is the period of the 'minute' hand on a mechanical clock?
3600 seconds.
The time it takes for the minute hand to come back to its starting position is 1 hour, or 3600 seconds.
A car accelerates from rest at a rate of 8 m/s/s. How fast is the car going after 2.5 seconds?
20 m/s
What is the weight of an 80 kg person near the surface of the Earth?
784 Newtons
What is a force?
A push or a pull that may change an object's state of motion.
What is the primary factor that causes the Earth to have seasons?
The Earth is tilted on its axis by about 23 degrees.
A toy car runs 12 laps in 84 seconds. The lap has a diameter of 4 meters. What is the tangential speed of the car as it goes around the lap?
1.8 meters per second
An object starts at 5 m/s and then speeds up to 15 m/s in a span of 8 seconds. What is the average speed of this object?
10 meters per second
According to Newton's Laws of Motion, how many different types of motion are there and what are they?
2 types: accelerated and non-accelerated motion.
Define the Normal Force
The force that appears when a surface is pushed on.
The force acts opposite to the pushing force and perpendicular to the surface being pushed on.
A baseball bat and a ball cost $1.10 together, and the bat costs $1.00 more than the ball, how much does the ball cost?
Ball must cost $0.05, and the bat must cost $1.05
A centripetal force F is applied to a mass moving at a constant speed v in a horizontal circle of radius r. If the radius is quadrupled and the speed is halved, what happens to the centripetal force acting on the mass?
1/16 of the original force
A car travels a distance of 200 meters in 10 seconds. The car then travels at 10 m/s for the next 30 seconds. What is the average speed of the car?
12.5 meters per second
A single proton is pushed with a 1 Newton force. What is the acceleration experienced by the proton due to the force?
6x10^26 m/s/s
Explain the difference between inertial and non-inertial frames of reference.
Inertial frame of reference is one that is at rest or at constant velocity. Within this frame of reference, you do not feel like you are moving. (Train moving at constant speed between stations)
Non-inertial frame of reference is one that is accelerating, that is changing speed or direction. Within this frame of reference, you will feel as if some force is pulling you around as the frame of reference accelerates. (Train speeding up or slowing down or rounding a turn)
In your cellar there are three light switches in the OFF position. Each switch controls 1 of 3 light bulbs on the floor above.
You may move any of the switches but you may only go upstairs to inspect the bulbs one time. How can you find the switch for each bulb with one inspection?
Number the switches 1, 2 and 3.
Switch on number 1 for 1 minute, then switch it off. Switch on number 2. Go upstairs...
The light that is on is connected to switch 2. The light that is off and warm is connected to switch 1. The light that is off and cold is connected to switch 3!
A 2 kg rock is whirling around in a horizontal circle on a string. The string can support a maximum tension of 48 Newtons and has a length of 1.5 meter.
What is the maximum speed and the maximum acceleration you can provide the rock without the string snapping?
tangential speed --> 6 m/s
centripetal acceleration --> 24 m/s/s
What is the final velocity of an object that is thrown vertically downwards with an initial speed of 2 m/s and falls for 5 spooky seconds?
About 52 meters per second
Two forces can produce a maximum net force of 143 Newtons together. The same two forces can produce a minimum net force of 33 Newtons.
What are the two forces?
55 Newtons and 88 Newtons.