# Physics 1

A key falls from a bridge that is 45 m above the water. It falls directly onto a model boat moving with constant velocity that is 12 m in front of the point of impact when the key is released. What is the speed of the boat?

A ball is thrown upward from the ground with an initial speed of 25 m/s; at the same instant, another ball is dropped from a building 15 m high. After how long will the balls be at the same height?

A pilot flys a plane at 120k km/h [E] with the wind from [W 30 S] @ 60 km/h. Find the resulting velocity.

A pilot flys a plane to a town that is 600km [N 30 E] and wants to arrive in 3 hours. The wind is from the west @ 60 km/h. What is the air speed and heading?

A pilot want to fly to a town 500km [N 38 E]. The plane is designed to fly at 170 km/h. The wind is from the west @ 60km/h. Find the heading, ground speed, and E.T.A.

A whiffle ball is tossed straight up, reaches its highest point, and falls back down. Air resistance is not negligible. Which of the following statements are true? i. The balls speed is zero a the highest point ii. The balls acceleration is zero at the highest point. iii. The ball takes a longer time to travel up to the highest point than to fall back down.

i only

ii only

i & ii only

i & iii only

i, ii, and iii

A truck driver travels three-fourths the distance of his run at once velocity, v, and then completes his run at one half his original velocity (1/2)*v. What was the trucker’s average speed for the trip?

0.85 v

0.80 v

0.75 v

0.70 v

0.66 v

An airplane traveling at 90 m/s at an elevation of 300 m drops a box of supplies to skiers stranded in a snowstorm.

At what horizontal distance from the skiers should the supplies be dropped?

Find the magnitude of the velocity of the box as it reaches the ground.

A stone is thrown off the top of a building from a height of 40.0 m. The stone has a launch of angle of 30 degrees and an initial velocity of 200 m/s.

How long is the stone in flight?

How far from the base of the building does it travel?

At what velocity, and at what angle, does the stone impact the ground?

An artillery shell is fired with an initial velocity of 110 m/s at an angle of 30∘above the horizontal. Find:

Its position and velocity after 6 s

The time required to reach its maximum height

The horizontal distance (range)

Find the range of a gun which fires a shell with muzzle velocity v0at an angle θ.

What is the range (your answer in terms of variables?)

Find the angel of elevation θof a gun that fires a shell with muzzle velocity of 115 m/s and hits a target on the same level but 1200 m distant.

Which angle for θgives the maximum possible range for a projectile. In terms of the remaining variables find the hang time, height, and range.

A stone is thrown off the top of a building from a height of 45.0 m. The stone has a launch of angle of 62.5 degrees and a speed of 31.5 m/s.

How long is the stone in flight?

How far from the base of the building does it travel?

What is its speed just before it hits the ground?

A student is swimming across a stream with velocity ⃗Vs= 6 m/s [E]. The water is moving downstream with velocity⃗Vw= 4 m/s [S]. What is the velocity of the student relative to another student sitting on the west bank of the river?

How long does it take to cross the river?

How far downstream does the swimmer go?

As shown in the figure, two blocks with masses m and M (M>m) are pushed by a force F in both Case I and Case II. The surface is horizontal and frictionless. Let R1 be the force that m exerts on M in Case I and RII be the force that m exerts on M in Case II. Which of the following statements is true?

Two boxes with masses 17 kg and 15 kg are connected by a light string that passes over a frictionless pulley of negligible mass as shown in the figure below. The surfaces of the planes are frictionless. The blocks are released from rest. T1 and T2 are the tensions in the strings. Which of the following statements is correct?

A toy car of mass 6 kg moving in a straight path, experiences a net force given by the function F = -3t. At time t=0, the car has a velocity of 4 m/s in the positive direction and is located +8 m from the origin. The car will come instantaneously to rest at time t equal to

2/3 s

sqrt( 4/3 ) s

sqrt( 8/3 ) s

sqrt( 8) s

4 s

In the situation above, what is the ratio of the masses?

0.67

1.0

1.4

1.5

1.6

Hercules and Carlos horizontally push in the same direction on a 1200 kg crate. Hercules pushes with a force of 500 N and Carlos pushes with a force of 300 N. If a frictional force provides 200 N of resistance, what is the acceleration of the crate?

1.3 m/s2

1.0 m/s2

0.87 m/s2

0.75 m/s2

0.5 m/s2