| A | B |
|---|
| A net force acting on a moving object causes the object to _____. | acceleration |
| ____ is the only downward force acting on a freely falling object. | gravity |
| What opposes acceleration of a falling object due to gravity? | air resistance |
| According to Newton's second law, acceleration depends on the size of the force and the ______ of an object. | mass |
| What force causes a leaf to fall more slowly than a penny? | air resistance |
| Which best illustrates Newton's third law? | Rocket propulsion |
| The _____ velocity of a projectile is considered to be constant. | horizontal |
| An object in free fall can be considered _____. | weightless |
| _____ is reached when air resistance and force due to gravity are equal in size. | Terminal velocity |
| what does not affect the amount of air resistance that acts on an object? | mass |
| Acceleration toward the center of a curved or circular path is _____. | centripetal acceleration |
| a motionless object has no _____. | momentum |
| What two forces are constantly acting on a satellite in Earth orbit? | gravity and air resistance |
| Because of Earth's gravitational pull and their own inertia, projectiles follow _____ paths. | curved |
| The momentum of a large bus is _____ that of a small car traveling at the same speed. | greater then |
| Force is expressed in units of | kg * m/s2 |
| Newton's second law can be expressed in equation form as _______. | f=ma |
| How much force is needed to accelerate a 75-kg skater and his 2.5-kg skateboard at 0.5 m/s2 | 38.75 N |
| Near Earth's surface, gravity causes all falling objects to accelerate at ______. | 9.8 m/s2 |
| An object that is thrown downward is affected by _______. | gravity and the downward force of the throwing hand |
| What is the highest velocity that will be reached by a falling object called? | terminal velocity |
| ball thrown horizontally from shoulder height will hit the ground _______ a ball dropped from the same height. | at the same time as |
| ______ are human-made devices that orbit Earth for a specific purpose. | Artificial satellites |
| The unit for ______ is kg × m/s. | momentum |
| The law of conservation of momentum states that the total amount of momentum of a group of objects does not change unless_______. | outside forces act on the objects |
| Newton's third Law of Motion | to every action force there is a equal and opposite reaction force |
| momentum | property of a moving object determined by multiplying its mass times its velocity |
| law of conservation of momentum | describes the unchanging nature of the total momentum of a system |
| air resistance | force that opposes the motion of falling objects near the Earth's surface |
| artificial satellite | human-made device that orbits the Earth |
| projectile | any object shot or thrown into the air |
| centripetal acceleration | acceleration toward the center of a circle |
| centripetal force | causes circular motion;force causing centripetal acceleration |
| Newton's second Law of Motion | describes the effect of a net force on an object;F=ma |
| terminal velocity | achieved when the air resistance balances the acceleration due to gravity |
| geostationary | object orbiting the Earth at same rate Earth is turning |
| weightless | object in free-fall;free from the effects of gravity |
| momentum= | p=mv (p=momentum, m=mass, v=velocity) |
| Newton's thirs law of motion | "to every action there is an equeal and opposite reaction" |
| If a 2-kg ball is thrown though the air at 20 m/s, what is the momentum of the ball? | 40 kg*m/s ((p=mv, 2kg * 20 m/s=) |
