Forces

A pumpkin shot at an angle of 60^o above the horizontal strikes a building 2.38 seconds later, 80 ft away at a point 48 ft above the point of projection. (keep units as they are, g = 32ft/s²)

(a) Find the initial velocity v_i = 67.3 ft/sec.

(b) Find the magnitude & direction of the velocity when it strikes the building.

38.1 ft/s, 28 ^o

Draw a free-body diagram for a ball resting on a table.  Be sure to label all forces. 

Draw a free-body diagram for a ball rolling down a hill.  Label all forces. 

1.   Draw the free body diagram for a ball that’s dropped (while it’s in the air).

2.   Draw the free body diagram for a box pulled on a table at a constant speed.

3.   A 60 kg man pushes a 15 kg box across a floor using a force of 60 N.

1.   What is the mass of the box?

2.   What is the force of gravity on the box?

3.   Draw a free-body diagram of the box.

4.   What is the magnitude of the normal force on the box?

5.   How hard does the box push on the ground?

6.   How hard does the box push on the man?

Horizontal Projectile Motion

Jes throws Mati a baseball 42 m/s horizontally from a height of 2m. How far will the ball travel before it reaches the ground?

26.88 m

Clara shoots a pool ball off of a 0.60-meter high table with an initial horizontal velocity of 2.4 m/s. Predict the time required for the pool ball to fall to the ground and the horizontal distance to the ball's landing location.

t = 0.350 s

x = 0.84 m

Horizontal Projectiles

A soccer ball is kicked horizontally off a 22.0-meter high hill and lands a distance of 35.0 meters from the edge of the hill. Determine the initial horizontal velocity of the soccer ball.

16.5 m/s.

10/9/14 Adding Vectors

A pilot starts to fly due north for 20 km, then, he turns left (20 degrees West of North) for 5 km.  He finally turns around completely (70 degrees East of South) for another 20 km.  What is his final displacement?  (remember, displacement has both a magnitude and a direction)

7.82 km, 49 degrees North of Ea