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Newton's Laws of Motion Conceptual
Terms in this set (36)
All forces are ____
What is normal force?
The force of the surface pushing on the object and keeping it from passing through
Which has more inertia, a MAC truck or roller skate?
MAC truck because it has much more mass and is less willing to change direction
True or false: The normal force is always = to the weight of an object
T or F: Tension is always pointing straight up
A car is rolling down the street. What type of friction is acting on it?
A car is parked on a hill. What kind of friction is acting on it?
Which is greater for an object: Force due to friction static, or force due to friction kinetic?
Which of the following will have a higher coefficient of friction? Rubber on gravel/wax paper on linoleum
Rubber on gravel
Which of Newton's Laws is the coin, notecard, and beaker demonstration an example of? Explain it.
First Law- coin fell into beaker when notecard was quickly pulled away because its inertia kept it in place
A skydiver leaps from an airplane. Ignoring air resistance, what is his acceleration? How does air resistance affect his acceleration?
-9.81 m/s^2 with no air resistance, with air resistance acceleration will approach 0
An elephant and a feather are dropped form a tall building. Which encounters more air resistance and why?
Elephant is larger and more massive, so experiences a greater drag
An elephant and a feather are dropped form a tall building. Which falls faster and why?
The elephant because it takes much longer for this drag force to build up and the elephant to reach terminal velocity
What happens to acceleration if: F is doubled, m stays constant
What happens to acceleration if: F stays constant, m is doubled
What happens to acceleration if: F is quadrupled, m is doubled
What happens to acceleration if: F is halved, m stays constant
What happens to acceleration if: F is halved, m is quadrupled
acceleration is divided by 8
Action: Foot pushes down on ground with 10 N of force
Ground pushes up on foot with 10 N
Action: Earth pulls down on object with 100 N of force
Object pulls up on earth with 100 N
Every time you drop an object, it pulls the earth up. How can this be true if we do not see the earth move?
The force acting on the earth and the object have the same magnitude. The mass of the earth is extremely large, so therefore it must have an extremely small acceleration to balance out with the object having a larger acceleration and small mass.
If you throw a rock in outer space away from gravitational or frictional influences, what will the rock do?
Continue moving in a straight line at constant speed (inertia)
Which force is greater: The earth pulling on the moon, or the moon pulling on the earth?
They are =
When a pellet fired into a spiral tube emerges, which way will it travel?
Straight out of tube
If a mac truck and a volkswagen have a head on collision, which vehicle will experience the greater impact force?
Both the same (little car just takes it worse)
If you hold a book against the wall and it is stationary, which way does friction act?
If you hold a book against the wall so that it slides upwards, which way does friction act?
Two smooth balls of exactly the same size, one wooden and one iron are dropped. Which will encounter greater air resistance?
If you have a pulley and block on a flat surface, which will accelerate faster: With a block attached to the end of the pulley, or a hand pulling down on the rope?
The hand because although the applied force is the same, there is twice the mass in the first situation that the force must move
If you have a rope between two 100N blocks hanging off either side of a table, what will the scale in the middle of the rope read?
Why do cars have headrests?
When you are rear ended, your head stays in the same place in relation to the road, but your body moves forward with the car. So your head would snap back in relation to the vehicle, but the head rest helps it to move forward.
How does Newton's 3rd Law let you walk?
Your feet push back on floor, and the floor pushes you forward
Why do normal car tires have treads? Why do racing cards have no treads?
Normal tires have treads so water can run off and car doesn't hydroplane. Racing tires don't have treads so there is more friction and an increased grip on the road so they can do turns better.
When does terminal velocity happen?
Fw = F drag
How does a parachute work?
Increases cross sectional area, so air drag becomes larger, slowing acceleration. The larger the parachute, the slower the descent.
Difference between mass and weight?
Mass= amount of matter, constant everywhere, kg, measure with balance
Weight= depends on gravity, N, is a force, vector quantity, measured with scale