Abdualla

A small rock is thrown vertically upward with a speed of 18.0 m/s from the edge of the roof of a 39.0 m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected.

Part A

What is the speed of the rock just before it hits the street?

Express your answer with the appropriate units.

Part B

How much time elapses from when the rock is thrown until it hits the street?

Express your answer with the appropriate units.

A car sits in an entrance ramp to a freeway, waiting for a break in the traffic. The driver sees a small gap between a van and an 18-wheel truck and accelerates with constant acceleration along the ramp and onto the freeway. The car starts from rest, moves in a straight line, and has a speed of 24.0 m/s when it reaches the end of the ramp, which has length 125 m .

Part A

What is the acceleration of the car?

(unit in m/s^2)

Part B

How much time does it take the car to travel the length of the ramp?

(Unit in s)

Part C

The traffic on the freeway is moving at a constant speed of 24.0 m/s . What distance does the traffic travel while the car is moving the length of the ramp?

(unit in m)

A rocket starts from rest and moves upward from the surface of the earth. For the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay=(3.00m/s3)t, where the +y-direction is upward.

Part A

What is the height of the rocket above the surface of the earth at t = 10.0 s ?

Express your answer with the appropriate units.

Part B

What is the speed of the rocket when it is 345 m above the surface of the earth?

Express your answer with the appropriate units.

Ricardo and Jane are standing under a tree in the middle of a pasture. An argument ensues, and they walk away in different directions. Ricardo walks 23.0 m in a direction 60.0 ∘ west of north. Jane walks 16.0 m in a direction 30.0 ∘ south of west. They then stop and turn to face each other.

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1) What is the distance between them?

"Express your answer with the appropriate units"

2) In what direction should Ricardo walk to go directly toward Jane?

"The answer should be in east of south"

A jet plane is flying at a constant altitude. At time t1=0 it has components of velocity vx= 92 m/s , vy= 109 m/s . At time t2= 27.0 s the components are vx= 161 m/s , vy= 37 m/s .

Part A

For this time interval calculate the average acceleration.

Give your answer as a pair of components separated by a comma. For example, if you think the x component is 3 and the y component is 4, then you should enter 3,4. Express your answer using two significant figures.

Part B

Find the magnitude of the average acceleration.

Express your answer using two significant figures.

Part C

Find the direction of the average acceleration (let the direction be the angle that the vector makes with the +x-axis, measured counterclockwise).

The acceleration of a bus is given by ax(t)=αt, where α = 1.16 m/s3 is a constant.

Part A

If the bus's velocity at time t1 = 1.02 s is 5.00 m/s , what is its velocity at time t2 = 2.06 s ?

Part B

If the bus's position at time t1 = 1.02 s is 6.05 m , what is its position at time t2 = 2.06 s ?

Two workers pull horizontally on a heavy box, but one pulls twice as hard as the other. The larger pull is directed at 25.0 ∘ west of north, and the resultant of these two pulls is 440.0 N directly northward.

Part A

Use vector components to find the magnitude of each of these pulls. Assume that the smaller pull has a component directed to the north.

Enter your answers numerically separated by a comma.

A 4.50 kg bucket of water is accelerated upward by a cord of negligible mass whose breaking strength is 74.0 N .

Part A

If the bucket starts from rest, what is the minimum time required to raise the bucket a vertical distance of 10.0 m without breaking the cord?

(Express your answer with the appropriate units.)

A demolition crew uses dynamite to blow an old building apart. Debris from the explosion flies off in all directions, and is later found at distances up to a distance 45.0 m from the explosion

Part A

Find the maximum speed at which debris was blown outward by the explosion. Neglect air resistance.

A juggler performs in a room whose ceiling is a height 3.5 m above the level of his hands. He throws a ball upward so that it just reaches the ceiling.

Part A

What is the initial velocity of the ball?

Express your answer using two significant figures ??

Part B

What is the time required for the ball to reach the ceiling?

Express your answer using two significant figures.

Part C

At the instant when the first ball is at the ceiling, he throws a second ball upward with two-thirds the initial velocity of the first. How long after the second ball is thrown did the two balls pass each other?

Express your answer using two significant figures.

Part D

At what distance above the juggler's hand do they pass each other?

Express your answer using two significant figures.

Part A

If the bus's velocity at time t1 = 1.02 s is 5.00 m/s , what is its velocity at time t2 = 2.06 s ?

Part B

If the bus's position at time t1 = 1.02 s is 6.05 m , what is its position at time t2 = 2.06 s ?

Part A

What is the car's acceleration?

Part B

How far does the car travel while it accelerates?

Part A

What is the distance of the second post from you, if the distance between the two posts is 90.0 m ?

Express your answer with the appropriate units.

An explorer in the dense jungles of equatorial Africa leaves his hut. He takes 42 steps at an angle 45 ∘ north of east, then 79 steps at an angle 60 ∘ north of west, then 53 steps due south. Assume his steps all have equal length. Save him from becoming hopelessly lost in the jungle by giving him the displacement, calculated using the method of components, that will return him to his hut.

The angle between vector A⃗ = 2.00 i^ + 3.00 j^ and vector B⃗ is 45.0°. The scalar product of vectors A⃗ and B⃗ is 3.00. If the x component of vector B⃗ is positive, what is vector B⃗ .

Two workers pull horizontally on a heavy box, but one pulls twice as hard as the other. The larger pull is directed at 25.0 ∘ west of north, and the resultant of these two pulls is 440.0 N directly northward.