Forces
What tool is used to measure force?
Spring Scale
Why does the sun have a stronger gravitational pull on the earth than the moon?
the mass of the sun is much greater than the moon
Explain why it is easier to slip on floor that is wet.
because there is less friction between your shoe and a wet floor and your shoe and a dry floor
If I want to increase motion, while mass stays the same, what should I do to the force?
give an example
increase force
the man swings with a hammer to hit the bell instead of the boy
What do all changes in motion require?
Force
When more than one force act together, sometimes there is no change in motion. These are ________________ forces.
balanced
What two factors affect the force of Gravity?
Mass and distance
Why do you put grease on the chain of your bicycle?
to reduce friction
If I want to increase motion, while force stays constant, what should I do to mass?
give an example
decrease mass
throw a ball with less mass
_____________ is the force of attraction between two objects.
Gravity
What is the result of unbalanced forces acting on an object?
the object speeds up, slows down, stops or changes direction
A spring scale is used to weigh a block. The force on the block is 3 N.
What would the spring scale read if an identical second block was added to the hook?
6 N
When is friction desirable? Give an example.
If you need grip or traction to complete a task. The grip on bike tires.
If gravity pulls down on the piece of metal that rings the bell with a force of 10 N, how much force is needed to cause the piece of metal to rise?
a force greater than 10 N
________________ is the force that opposes motion - meaning it usually is in the opposite direction of the applied motion.
Friction
Two teams have a tug of war.
The four players on team A pull with forces of 80 N, 120 N, 130 N, 90 N
Team B has four players that pull with forces of 100 N, 100 N, 90 N, 90 N
Which team will win? Why?
Team A with a total of 420 N. Team B has only 380 N.
When a comet is travelling in space, what might cause its speed or direction to change?
passing by another planet with a strong gravitational force
When do we need to overcome friction? Give an example.
When we need smoothness or fluidity to complete a task. Bowling a ball
Two trucks both brake at the same time with an equal force. One truck has a full load, while the other is empty. Which truck will stop first?
The empty truck or the loaded truck?
the empty truck
A car pulls away from a stoplight. What kinds of forces are acting on the car?
unbalanced forces
________________ is a measure of the force that gravity exerts on an object.
Weight
A box is placed on a table. What should the normal force (Fn) acting on the box be compared to the gravitational force?
gravitational force and normal force should be equal
What is a side effect or by product of Friction? (HINT: it is a type of energy)
heat
If you want to slide a heavy box across the floor faster you have two options. What are they? Use examples to explain.
decrease the mass of the box by taking stuff out
increase the force by getting a friend to help
When a plane flies at a constant velocity, all the forces acting on the plane are _______________.
balanced forces