# Physics 1: Kinematics

A car accelerates at 3 m/s$^2$ from rest for 10 s. How far does it travel?

A car is moving at 100 km/h. It stops in 5.0 s. What is the car's acceleration?

A ball is thrown off a building. If the ball is thrown up at 5 m/s and lands 3 seconds later

Find the height of the building

Find the impact velocity of the ball

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?

An object is projected straight upward from the ground level with a velocity of 50 m/s. Ignoring air resistance, it will return to the ground in approximately how many seconds?

A Jogger runs with constant speed $v$ through a forest of pine trees. A pine cone starts to fall from a height $h$ when the jogger is directly below it. How far behind the jogger will the pine cone land?

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 projectile is launched off a click at an angle. The cliff is 15m high, the projectile is launched at 25 degrees above horizontal. How much time is the projectile in the air before hitting the ground?

A swimmer is capable of swimming 0.60 ni/s in still water. (a) If she aims her body directly across a 55-m-wide river whose current is 0.50 m/s, how far downstream (from a point opposite her starting point) will she land? (b) How long will it take her to reach the other side?

In a rescue attempt, a hovering helicopter drops a life preserver to a swimmer being swept downstream by a river current of a constant velocity v. The helicopter is at a height of 9.8 m. The swimmer is 6.0 m upstream from a point directly under the helicopter when the life preserver is released. It lands 2.0 m in front of the swimmer. How fast is the current flowing? Neglect air resistance.

13.7 m/s

9.8 m/s

6.3 m/s

2.8 m/s

A river is 300 m wide and the water flows downstream, exactly south, at 4 m/s. If a swimmer, moving at exactly 6 m/s, attempts to swim across the river:

At what direction should the swimmer orient himself to swim straight across the river in the east direction?

How long will it take the swimmer to across the river?

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 child tosses a ball directly upward. Its total time in the air is T. Its maximum height is H. What is its height after it has been in the air at time T/4? Neglect air resistance.

H/4

H/3

H/2

2H/3

3H/4

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

On a good dry road, a car with good tires may be able to brake with a constant deceleration of 4.92 m/s$^2$ . How long does such a car initially traveling at 24.6 m/s take to stop? How far does it travel this time?

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 student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of 18.0 m/s. The cliff is 50.0 m above a flat, horizontal beach as shown in the figure. (a) What are the coordinates of the initial position of the stone? (b) What are the components of the initial velocity? (c) Write the equations for the x- and y-components of the velocity of the stone with time. (d) Write the equations for the position of the stone with time, using the coordinates in the figure. (e) How long after being released does the stone strike the beach below the cliff? (f) With what speed and angle of impact does the stone land?