2011 Midterm Review

PhysicsMs. Allison

a. more.b. unchanged.c. less.

An airplane flying into a head wind loses ground speed, and an airplane flying with the wind gains ground speed. If an airplane flies at right angles to the wind, then ground speed is

Answer

• An airplane flying into a head wind loses ground speed, and an airplane flying with the wind gains ground speed. If an airplane flies at right angles to the wind, then ground speed is

a. more.

a. in the direction of motion.b. opposite its velocity.c. directed downward.d. directed upward.

A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

c. directed downward.

A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

Answer

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

a. arrow's push against the bowstring.

b. weight of the arrow.c. friction of the ground against the

archer's feet.d. air resistance against the bow.

a. arrow's push against the bowstring.

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

Answer

a. Linear speedb. Tangential speedc. Rotational speed

d. Centripetal force.

A car driving straight down the street has

a. Linear speed

A car driving straight down the street has

Answer

What do we know about energy based on the conservation of energy?

What do we know about energy based on the conservation of energy?

According to the conservation of energy, we know the energy is neither loss or created only transferred from one form to another.

Answer

a. that changes as a person bends over.

b. that is fixed, though different for different people.

c. that is always directly behind the belly button.

d. none of the above

The center of gravity of a human body is located at a point

Answer

a. that changes as a person bends over.

The center of gravity of a human body is located at a point

a. The inside horseb. The outside horsec. Neither—they both have the

same tangential speed.

Which has greater tangential speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

Answer

b. The outside horse

Which has greater tangential speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

a. The inside horseb. The outside horsec. Neither—they both have the

same rotational speed.

Which has greater rotational speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

Answer

c. Neither—they both have the same rotational speed.

Which has greater rotational speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

a. direction.b. magnitude.c. time.d. color.

A scalar is a quantity that has

Answer

b. magnitude.

A scalar is a quantity that has

a. The mounted tire, provided the tire is more massive than the rim

b. The tire alone, provided it is as heavy as the rim

c. The tire alone, regardless of its weightd. The mounted tire, regardless of its

weight

Which rolls to the bottom of a hill sooner, a car tire alone or the same tire mounted on a rim?

Answer

c. The tire alone, regardless of its weight

Which rolls to the bottom of a hill sooner, a car tire alone or the same tire mounted on a rim?

What has more influence on kinetic energy; mass or velocity?

Answer

What has more influence on kinetic energy; mass or velocity?

Velocity because it is squared in the kinetic energy equation

• What is the relationship between kinetic energy and conservation of energy?

Answer

• What is the relationship between kinetic energy and conservation of energy?

Kinetic energy is the energy of motion. When one moving object hits another, the energy is transferred between the objects since energy cannot be creates nor destroyed according the law of the conservation of energy.

• How fast does Kenny run the 100 m dash if he crosses the finish line in 10 s?

Answer

Knownd = 100mt = 10sUnknown vEquationv = d/t

Solve v = d/t = 100 m 10s = 100 m/s

About how tall is a tree, if it takes 1.2s for an apple to fall to the ground from the very top branch?

Answer

Known t =1.2s g = 10m/s2

vo = 0

Unknown dEquation d = vot + ½ gt2

Solved = vot + ½ gt2

= (0)(1.2s) + ½(10m/s2)(1.2s)2

= ½(10m/s2)(1.2s)2

= ½(10m/s2)(1.44s2) = (5m/s2) (1.44s2) = 7.2 m

• Michael is 75kg and runs up the a 5 m high hill in 25s. What is his power input?

Answer

Known m = 75kg d = 5m t = 25sUnknownPowerEquationPower = W/t

SolvePower = W/t = Fd/t (remember Force times distance is work)

= mgd/t (remember Force is mass times gravity)

= (75kg)(10m/s2)(5m) 25s = 3750 kg m2/s2

25s = 150 W