Motion, Acceleration & Gravity
What is the difference between distance and displacement?
Distance is the total length of the path traveled, and displacement is the change in position from start to end and it is also a vector quantity.
What is force and what is net force?
Force is a push or pull one body exerts on another. Net force is the sum of all of the forces combined together acting on an object.
What is work? What is Power?
Work, in Joules is the product of force and displacement. Work is done on objects when a force acts on the object in the direction the object moves, Work=force*displacement. Power, in Watts is the rate of doing work, Power=work/time.
What is speed?
Speed is the rate of change in position. It is not defined as how fast something is going.
Speed and Velocity: A child in an airport is able to cover 291 meters in 3 minutes running at a steady speed down a moving sidewalk in the direction of the sidewalk's motion. Running at the same speed in the direction opposite to the sidewalk's movement, the child is able to cover 228 meters in 4 minutes. What is the child's running speed on a still sidewalk, and what is the speed of the moving sidewalk?
The child's running speed is 77m/min and the sidewalk speed is 20m/min.
What is acceleration and what is gravity?
Acceleration, in meters per second squared is the rate of change in velocity. Gravity is a force of attraction between two objects due to their mass and distance between them. The acceleration due to gravity is 9.8.
What are balanced forces? What are unbalanced forces?
Balanced forces are forces on an object that are equal in size and opposite in direction. Unbalanced forces are two forces acting on an object that are opposite in direction but not equal in magnitude.
Energy is the ability to do work and cause a change.
What is velocity?
Velocity describes speed and direction. It is the rate of change in position with a direction.
Force: A sponge, of mass 250 grams, falls vertically down from a window cleaner’s hand when he is cleaning a high rise office block. It experiences a 1 N force of air resistance. What is the net force acting on the sponge? If the sponge reached terminal velocity, what would be the force of air resistance?
1.45N
Acceleration & Gravity: A person is skydiving for the first time and wants to calculate his terminal velocity. If he starts from rest and reaches his terminal velocity after 10.8 seconds of free falling, what was his terminal velocity?
105.84m/s
What is the difference between mass and weight?
Mass is a scalar quantity that is a measurement of how much matter an object is made of. Weight is a force that results from the force of gravity pulling objects towards the center of a large body.
How far can a mother push a 20.0 kg baby carriage, using a force of 62 N, if she can only do 2920 J of work?
47.1m
What is the difference between a vector quantity and a scalar quantity?
A vector quantity is a mathematical quantity with magnitude and direction (ex. force, velocity, displacement, and acceleration). A scalar quantity is a mathematical quantity with only magnitude (ex. mass, time, speed, and direction).
Acceleration & Gravity: You are traveling in a car that is moving at a velocity of 20 m/s. Suddenly, a car 10 meters in front of you slams on its brakes. At that moment, you also slam on your brakes and slow to 5 m/s. Calculate the acceleration if it took 2 seconds to slow your car down.
-7.5m/s2
A piece of glitter was falling through the air. If it started from rest what was the velocity of the glitter after 1.2 seconds?
vf= -11.772 m/s
What is Horse Power?
Horse power is a unit developed based on power outputs of very strong horses. The unit for horse power is hp.
How much power is used to move a 5 kg stationary object 84 feet in 8 seconds?
3.2w
What are the three different types of speed/velocity?
They are instantaneous, constant, and average.
The water in the Buffalo River flows at an average speed of 5 km/hr. If you and a friend decide to float down the river a distance of 16000 meters, how many hours will it take?
3.2hrs
A ball is dropped from the top of a building. After 2 seconds, its velocity is measured to be 19.6 m/s. Calculate the acceleration for the dropped ball if it started from rest.
9.8m/s2
Force: A unicorn is pushing a narwhal with a force of 26 N to the left. The narwhal is pushing on the unicorn with a force of 40 N to the right. What is the net force of this interaction? What is the direction of the net force?
14N to the right
Calculate the work done by a 47 N force pushing a pencil 26 cm.
12.22J
A car is traveling at 100 km/hr. How many hours will it take to cover a distance of 750 km?
It will take 7.5 hours to cover 750 km.
A car is traveling at 100 km/hr. How many hours will it take to cover a distance of 750 km?
7.5 hrs