Physics Final test

An object is fired from the ground at 100 meters per second at an angle of 30 degrees with the horizontal. Calculate the horizontal and vertical components of the initial velocity. After 2.0 seconds, how far has the object traveled in the horizontal direction? How high is the object at this point?

100cos30°= 86.60 m/s Horizontal component 100sin30°=50 m/s Vertical component Y= Viy(t)+½gt^2 Y=50(2)+(½)*(-9.81)(4) Y=80.38 meters high at 2 seconds.

Woods takes 2 hours to drive to the airport in the morning, but he takes 3 hours to return home over the same route. If his average morning speed is 20 mph faster than his average evening speed, how far is it from his home to the airport?

2(x+20)=3x (x is mph) x=40 60*2=120 His home is 120 miles from the airport

Miss Dalton, the tri-athlete, is swimming in the Cape Cod Canal. She swims North East at 2.5 MPH. The current is flowing South West at 0.8 MPH. Find Miss Dalton's resulting velocity (speed and direction).

2.5mph-0.8mph=1.7mph North East

Two high-speed ferries leave at the same time from Ft. Myers, Florida, going to Key West, Florida. The first ferry, the Cat, travels at 34 miles per hour. The second ferry, the Bird, travels at 28 miles per hour. In how many hours will the two ferries be 6 miles apart?

34-28=6 In one hour, the ferries will be 6 miles apart.

A plane is traveling at 400 mph bearing 20° (bearings are measured from North in a clockwise manner). How fast is the plane traveling North? How fast is the plane traveling East?

400cos20°=375.88m/s East 400sin20°=136.81m/s North

A train averaging 50 mph leaves San Francisco at 1 P.M. for Los Angeles 440 miles away. At the same time a second train leaves Los Angeles headed for San Francisco on a parallel track traveling at an average rate of 60 mph. At what time will the trains meet?

50x+60x=440 (x is time) 110x=440 x=4 At 5pm, both trains will meet.

A Jet Blue airplane leaves Chicago for New York at the same time a Southwest airplane leaves New York for Chicago. The distance from Chicago to New York is 821 miles. If the Jet Blue plane travels at 560 miles per hour and the Southwest plane travels at 580 miles per hour, how long into their flight will the two planes pass each other? Round your answer to the nearest hundredth of an hour.

560x+580x=821 x=.72 It will take .72 hours for the two planes to pass each other.

A jet plane flying at a speed of 600 mph is to overtake a bi-plane which started 3 hours earlier and which is flying at a speed of 400 mph. How long will it take the faster plane to overtake the slower plane?

600*6=3,600 and 400*9=3,600 It will take the faster plane 6 hours to overtake the slower plane

Projectile Motion:

A form of motion in which an object or particles thrown near the earth's surface, and it moves along a curved path under the action of gravity only.

Linear Motion:

A motion along a straight line, and can therefore be described mathematically using only one spatial dimension.

Vector:

A quantity having direction as well as magnitude, especially as determining the position of one point in space relative to another.

Distance:

An amount of space between two things or people.

Time:

An interval in a continuum of two points. The duration (somewhat)

Betty drives for a number of hours at 70 miles per hour. When traffic slows, she drives at 50 miles per hour for 30 minutes longer than she traveled at 70 miles per hour. She traveled 5 miles more at 50 mph than 70 mph. Determine how long Betty traveled at 50 miles per hour.

Betty traveled 75 miles at 50mph. x=Time, y=Distance 70x=y, 50(x+.5)=y+5 50(x+.5)=70x+5 20=20x x=1 50*1.5=75

Acceleration:

Change in the rate or speed of something.

Free Fall:

Downward movement under the force of gravity only.

Scalar:

Having only magnitude, not direction.

Acceleration due to Gravity:

It is the force that a planet exerts (Earth 9.81m/s^2)

Linear Motion with Constant Acceleration:

If it has uniform velocity, the acceleration is zero. If acceleration is uniform and constant, it doesn't change, the velocity increases and it is positive. Velocity and acceleration in the same direction. If velocity goes right and acceleration down, then velocity decreases and acceleration remains constant up until it reaches 0m/s.

Angle:

It is the direction from a particular reference point.

Displacement:

Moving in a specific direction of something from its place or position.

Physics:

Science that studies matter energy and space including, but not limited to, cosmology, energy, forces. I tries to answer the Why.

Direction:

The course of path on which something is moving or pointing.

What is the difference between a vector and a scalar?

The difference between a vector and a scalar is that they both include magnitude, but vector tells us the direction where as the scalar doesn't.

Units:

The measurement or standard that is measured by everything.

Speed:

The rate at which someone or something is able to move.

Magnitude:

The size or extent of something.

Velocity:

The speed of something in a given direction.

Resultant Vector:

The sum or combined effects of two vectors.

Components:

The two directions in which the resultant vector comes from.

Suppose an object is in free fall. Each second the object falls

b. a larger distance than in the second before.

A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is

a. 0 m/s2.

Speed is

a. a measure of how fast something is moving. b. always measured in terms of a unit of distance divided by a unit of time. c. the distance covered per unit time. d. all of the above.

As an object falls freely in a vacuum, its

a. velocity increases.

A car starts from rest and after 7 seconds it is moving at 42 m/s. What is the car's average acceleration?

c. 6 m/s2

In the absence of air resistance, objects fall at constant

c. acceleration.

A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be

c. the same as the speed it had when thrown upwards.

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

d. instantaneous speed.