chapter 10: projectile motion

MATH: a package falls out of a helicopter that is traveling horizontally at 80 m/s. it falls into the water below 6.0 seconds later. assuming no air resistance, what is the horizontal distance it travels while falling?

480 m vertically

If you throw a stone horizontally from the top of a cliff, one second after leaving your hand its vertical distance below the top of the cliff is

5 m

a projectile is launched vertically upward at 50 m/s. if air resistance is negligible, its speed upon returning to its starting point is

50 m/s

a bullet is fired horizontally with an initial velocity of 300 m/s from a 20m high tower. if air resistance is negligible, the bullet hits downrange about

600 m

a projectile is launched from ground level at 15 degrees above the horizontal and lands downrange. What other projection angle for the same speed would produce the same down-range distance?

75 degrees.

which of these vary for satellites in elliptical orbits?

all of the above kinetic energy, speed, momentum

the circular path of a satellite orbiting earth is characterized by a constant

all of the above speed, acceleration, radial distance

Project a cannonball from atop Newton's hypothetical mountain at 8 km/s and it orbits Earth. Project it at 9 km/s and the shape of the orbit is

an ellipse

a bullet fired horizontally from a rifle begins to fall

as soon as it leaves the barrel

as soon as a ball rolls of the edge of a table

it is not acted on by any horizontal forces

when the potential energy of a satellite decreases

its kinetic energy correspondingly increases

Ideally, a ball is thrown up at an angle and lands downrange. Because of air resistance, the distance reached is

less

a ball is thrown upward and caught when it returns. compared with its initial speed and in the presence of air resistance, the speed with which it is caught is

less

a projective is launched vertically upward at 50 m/s. if air resistance does affect motion, then its speed upon returning to its starting point is

less than 50 m/s

minimal orbital speed about earth is about 8 km/s, and about the moon is

less than 8 km/s

An object is thrown vertically into the air. In this case air resistance affects motion. Compared with its time for ascent, the time for its descent is

longer

from earth, one satellite appears to overtake another. the faster satellite is

lower

the mood does not crash into earth because

moon has a sufficient tangential speed

a lunar month is about 28 days. if the moon were from earth than it is now, the lunar month would be

more than 28 days

an earth satellite in an elliptical orbit travels fastest when it is

nearest earth

an astronaut at earth's surface has a mass of 50kg and a weight of 500 N. If she were floating freely inside a space habitat in remote space, she would have

no weight and the same mass

what prevents satellites such as the ISS from falling

nothing

acceleration is greater for a satellite when it is at the

perigee (closest point)

A rocket coasts in an elliptical orbit about the Earth. To attain escape velocity using the least amount of fuel in a brief firing time, should it fire off at the apogee, or at the perigee? (Hint: Let "Fd = change in KE" guide your thinking.)

perigee, where it is closest and fastest

the fastest moving planet in a solar system is the

planet nearest the sun

a projectile that is fired vertically from the surface of Earth at 5 km/s will

rise and fall back to earth's surface

nellie tosses a ball upward at an angle. assuming no air resistance, which component of velocity changes with time?

the vertical component

MATH: in a standing jump, the hang time of a certain athlete is 0.4 second. what is her hand time when she jumps the same height while moving horizontally?

.4 seconds (it wont affect her)

a gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. neglecting air resistance, how far downrange will the bullet be 1 second later

100 m

MATH: a ball is thrown horizontally from the top of a tall cliff. neglecting air drag, what vertical distance has the ball fallen 5.0 seconds later?

125m

A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The player sees the ball land 20 m down range. The player's pitching speed is about

20 m/s

Two projectiles are fired from ground level at equal speeds but different angles. One is fired at an angle of 30 degrees and the other at 60 degrees. Neglecting air resistance, the projectile to hit the ground first will be the one fired at (neglect air resistance)

30 degrees

a projectile is fired into the air at an angle of 50 degrees above ground level and hits a target downrange. It will also hit the target if fired at an angle of

40 degrees

MATH: a ball is thrown upward. its initial vertical component of velocity is 30m/s, and its initial horizontal component of velocity is 25 m/s. what are the horizontal and vertical components of the ball's velocity 4 seconds later?

?

MATH: kyle throws a ball horizontally from the top of a building that is 5.0 m high. he hopes the ball will reach a swimming pool that is at the bottom of the building. 12.0 m horizontally from the edge the building. if the ball is to reach the pool, with what initial speed must kyle throw it with?

?

MATH: a ball is thrown upward. its initial vertical component of velocity is 40 m/s and its initial horizontal component of velocity is 5 m/s. what is the ball's speed 1.0 s later?

?

MATH: a ball is thrown upward. its initial vertical component of velocity is 50 m/s and its initial horizontal component of velocity is 25 m/s. what is the balls speed 6 s later?

?

a satellite coasting at constant speed in a circular orbit

is nevertheless accelerating

earth satellites are typically more than 100 km high so as to be above earth's

atmosphere

a ball rolls off the edge of a table at the same time another ball drops vertically from the same table. the ball to hit the floor first is the

both hit at the same time

when air drag affects the motion of projectiles, they don't travel

both of these as far, as high

the conservation of energy applies to satellites in

both of these elliptical orbit and circular orbit

the kinetic energy of a planet is maximum when it is

closest to the sun

while a rock thrown upward at 50 degrees to the horizontal rises, neglecting air drag, its vertical component of velocity

decreases

according to kepler, the paths of planets about the sun are

ellipses

The force of gravity does work on a satellite when it is in

elliptical orbit

according to kepler, the speed of a planet is slowest when it is

farthest from the sun

an earth satellite is simply a projectile

freely falling around earth

according to kepler, the line from the sun to any planet sweeps out equal areas of space

in equal time intervals

a hunter on level ground fired a bullet at an angle of 10 degrees ABOVE the horizontal while simultaneously dropping another bullet from the level of the rifle. which bullet will hit the ground first.

the one dropped

Dr. Chuck projects a ball horizontally from a lab bench. If the projection speed of the ball were greater, the time in the air would be

the same

Dr. Chuck projects a ball horizontally from a lab bench. The ball lands on a bullseye marked on the floor a horizontal distance away. Compared to the time for the ball to simply drop vertically from the bench, the time in the air for Dr. Chuck's projected ball is

the same

hang time is the time your feet are off the ground in a jump. if you jump upward inside a moving vehicle, your hang time will be

the same

After a rock thrown straight up reaches the top of its path and then falls a short distance, its acceleration is (neglect air resistance)

the same as at the top of its path

the orbital path of a satellite has two focal points. when both focal points are together

the satellite path is a circle