Question | Answer |
True or False - Without air resistance, the objects will fall at different speeds and hit the ground at different times. | False; they fall at a same speed and hit the ground at the same time. |
What is a differenc between mass and weight? | The mass is the amount of matter in an object and the weight is the amount of force is acting on an object. |
If the cable breaks on the elevator, you will be in _________. | Free-fall |
If the elevator goes up, you become _________. | Heavier. |
If the elevator goes down, you become _________. | Lighter |
Momentum = | Mass * Velocity |
What is net force? | The overall force to which an object responds to: change in momentum (mass * acceleration) |
When does the change of momentum occurs? | When the net force is not zero. |
Are there any net force acting on the car when it comes to a stop? | Yes |
Are there any net force acting upon an elevator when it is going up at a constant speed? | No. |
Are there any net force acting upon the moon when it orbits around Jupiter? | Yes |
Are there any net force acting upon the bus when it speeds up? | Yes |
Are there any net force acting upon the bicycle when it moves around in circles? | Yes |
How are people in spaceships weightless in space? | The spaceships travel so fast that they can orbit around the Earth without falling into it. |
In space, weightlessness is due to? | Constant state of free-fall. |
What is angular momentum? | Any object either moving along a curved path or spinning. |
How does the Earth have angular momentum? | It rotates (rotational angular momentum) and orbits around the Sun (orbital angular momentum). |
What do the light and gravity follow? | Inverse square law |
What does inverse square law explain? | The intensity decrease at distance squared (1/distance squared) |
What are examples of weightlessness? | -A person is falling off a chair -A person jumps on a trampoline -Astronuats float in space. |
What is Newton's first law of motion? | -An object moves in a same velocity unless a net force acts upon it. |
What is Newton's second law of motion? | -Force = mass * acceleration (change in momentum) |
Suppose you swing a ball with a string in circles and the string suddenly breaks, what happen to the ball? | The ball goes directly away from you in a straight line. |
What is Newton's third law of motion? | Any force has its opposite and equal reaction force. |
What is an example for Newton's first law of motion? | A spaceship moves across space without fuel. |
What is an example for Newton's second law of motion? | A person tries to move a bowling ball, but it doesn't move that much. |
What is an example for Newton's third law of motion? | A Space Shuttle liftoffs from space; it proppelled upward by an equal force but opposite to the gas expelled from the back. |
What is acceleration? | Change in velocity |
What is speed? | Change in distance over time |
What is velocity? | Speed and direction |