Physics Final

If Gary the snail travels 30cm in 4 minutes, what is his average speed in m/s? speed = ∆Distance/ ∆time

1 cm = 0.01 m 1 min = 60 seconds speed = ∆Distance/ ∆time .3/(4x60)= .00125

A ______ is directly proportional to an increase in acceleration, and an increase in ______ is inversely proportional to the force.

1. Force 2. Mass

In the absence of air resistance, a ball will travel at the greatest distance across the ground if it is thrown at an angle of about _____?

45°

A 17kg brick is at rest on the floor. Andrew then picks up the brick and raises it to a point where it has 900J of Gravitational Potential Energy. How much work did Andrew do to lift the brick? How high is the brick? PEtop=mgh

900J PEtop/ms=h 900/(17x9.8)=5.4m

A position-time graph for an object which is moving with a constant, positive velocity is shown. What will result?

A positive acceleration

if a nonzero net force is acting on an object, then the object is definitely______.

Accelerating

A change in the force of gravity acting on an object will affect the object's _______?

Acceleration

A measure of the quantity of matter is?

mass

Recoil Problem: An astronaut with a mass of 70.0 kg is outside a space capsule when the tether line breaks. To return to the capsule, the astronaut throws a 2.0kg wrench away from the capsule at a speed of 14m/s. At what speed does the astronaut move towards the capsule? m₁V₁¹=⁻m₂V₂¹

m₁V₁¹=⁻m₂V₂¹ V₁=[⁻m₂V₂]/m₁=[-2x14]/70.0=.4m/s

The Magnitude of the force of gravity acting on an object is?

related to its mass

An Estes toy rocket has a mass of .05kg yet can produce an acceleration of 47m/s². What net force acts on the rocket? F=ma

F = .05x47= 2.35N

Two perpendicular forces, one of 45N directed upward and the second of 60N directed right, act simultaneously on an object with a mass of 35kg. What is the magnitude of the resultant acceleration of the object? a=F/m Pythagorean Theorem for the Force: F = √(a²+b²)

F = √(45²+60²) = 75N a = 75N/35kg = 2.14m/s²

A _______ causes an object to start/stop moving or change direction.

Force

If a light stone is thrown at the same time another person drops a heavier stone, which will land first?

Galileo says that both stones fall together.

A relationship between two variables can be expressed as?

Graph, Ratio, or Slope

How can a stone drop from a cliff tell you how high you are?

Height = (1/2)x(the gravity(9.8))x(time²)

An airplane flyng into headwind loses ground speed, and an airplane with the wind gains ground speed. If an airplane is flying at right angles to the wind, the ground speed is _______?

increased

When you look at the speedometer in a moving car, you can see the car's ____________?

instantaneous speed

A bowling ball with a mass go 7.0kg strikes a pin that has a mass of 2.0kg. The pin flies forward with a velocity of 6.0m/s, and the ball continues forward at 4.0m/s. What was the original velocity of the ball? (m₁V₁⁰)+(m₂V₂⁰)=(m₁V₁¹)+(m₂V₂¹)

(m₁V₁⁰)+(m₂V₂⁰)=(m₁V₁¹)+(m₂V₂¹) (7xY)+(2x0)=(7x4)+(2x6) 7xY=40 Y=5.72m/s

A piper-cub aircraft travels with a speed of 185mi/hr with respect to the air. Determine the resultant velocity of the plane (magnitude only) if it encounters a 15mi/hr tailwind.

185+15=200mi/hr

In a two body elastic collision, the ___________ is conserved.

Kinetic Energy

What type of energy can do work because an object is moving?

Kinetic Energy

A vector is a quantity that has:

Magnitude and Direction

The most widely used system of units is?

Metric System

The impulse experienced by a body is equivalent to the body's change in _____?

Momentum

A 5kg bowling ball is lifted from the floor to a height of 1.5m. What is the increase in Potential Energy? PE=mgh

PE=mgh PE=5x9.8x1.5=73.5J

A skier costs down a very smooth, 13m high slope. If the speed of the skier on the top of the slope is 5m/s, what is his speed at the bottom of the slope? PEtop+KEtop=KEbottom

PEtop+KEtop=KEbottom mgh+KEtop=KEbottom mgh+{1/2}mv²={1/2}mv² (Mass crosses out) (9.8x13)+({1/2}5²=v² 127.4+12.5=v² v=11.8m/s

An 11kg flowerpot falls from a window ledge 12m above a sidewalk. What is the Kinetic Energy of the pot just as it reaches the sidewalk? PEtop=KEbottom

PEtop=KEbottom KE=PE=mgh=11x9.8x12=1293.6J

What type of energy can do work because an object can fall?

Potential Energy

What is the rate of doing work?

Power

What velocity must a 1340kg car have in order to have the same momentum as a 2680kg truck traveling at a velocity of 15m/s to the west? P=mV P/m = V

Ptruck = 2680x15 = 40,200kg∙m/s -so- Vcar = 40,200/1340 = 30m/s

5m/s^2

Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration?

An airplane travels with a ground speed velocity of 500m/s at an altitude of 2km. It has a care package for the forgotten people of Togoland. The pilot wants to make sure they get the package but isn't sure how far ahead he should drop it. Help him calculate how far away to release the package. Time to fall = √(2d/g) 1m = 0.001km

T = √[(2x2000)/9.8] = 20.2 seconds

A roller coaster is at rest on the top of the first big hill and has 4,500J of Gravitational Potential Energy. How much Kinetic energy does the roller coaster have at the bottom of the hill?

The Same!

the statement by Newton that for every there is an equal but opposite reaction is which of his laws of motion?

The Third

The slope of a line is?

The rate of change.

A position-time graph shows an object moving in the positive direction, if it has a straight line across, what does that mean?

There is a constant velocity and 0 acceleration

A position-time graph for an object moves in the positive direction. if it curves upward, what does it mean?

There is acceleration.

A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually does not break, because the egg dropped on the grass, had more _______ to stop.

Time

An elevator weighing 20,000N is supported by a steel cable. What is the tension in the cable when the elevator is accelerated upward at a rate of 3.00m/s²? F = mg+ma m x g=N

To get the mass, divide 20,000/9.8 F = 20,000 + (20,000/9.8)x3 = 20,204N

The cannon fires the cannonball horizontally from the top of a 10m tower. What is the initial velocity if the cannonball flies a total distance of 350m? V= ∆D/∆T T= √[(2xh)/g]

Total time = √[(2x10)/9.8] = 1.42 Seconds Velocity = 350m/1.42 Seconds = 246m/s

An airplane initially flying at a speed of 60.0m/s accelerates at 5.0m/s² for 600m. What is its final speed after this acceleration? Vf=√(Vi²+2ad)

Vf=√(60²+2(5)(500)) 92.74m/s

An 80N force pushes an object 10m across the floor. Find the amount of work that is done. W=FxD

W=FxD W=80x10=800J

Mr. G lifts a 100kg mass 3 Meters off the ground. How much work did he do? W=∆PE ∆PE=mgh

W=∆PE ∆PE=mgh=100x3x9.8=2940

A ball is thrown up into the air at some angle between 10 degrees and 80 degrees. At the very top of the ball's path, its velocity is_____?

Zero

An airplane with a mass of 1,200kg tows a glider with a mass of 600kg. If the airplane propellers provide a net forward thrust of 3,600N, what is the acceleration of the glide? a = F/m

a = 3,600/(1,300+600) = 2m/s²