2 D or not 2 D _______________________,___Name Per

Do problems algebraically first, then plug in #’s.

1. You are an incurable (if misguided) romantic. In an effort to impress your beloved, you scoop up a bouquet of flowers, put on your goggles and climb into a cannon. Your plan is to fire yourself through your beloved’s open penthouse window. The center of the window is located 35 vertical meters up from the level of the gun barrel as shown. The cannon will launch you with at an angle θ of 75o

degrees above the horizontal. You intend to enter the window at the high point of your flight.

C) How far back (Δx) should you pull the cannon back from the house wall?-8 pts-

D) Your beloved feels a slight chill shuts the window 2.5 seconds after you have launched. What happens?

θ = 750

Δy = 35 m

A) At what speed vo must you be launched to enter the window at the highpoint of your flight?

B) What will your velocity be when you pass through the window? Is this velocity dangerous?

Δx = ?

vo

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2. The B-52 Bomber shown here is 49 m long and is travelling 230 m/s relative to the ground, over a bombing range.*

A) Sketch the path of the bombs as seen in a side view in the ground’s reference frame.

B) About how far apart will the bomb craters be? Take any measurements you need directly from the picture.

*Adapted from H, R and W, Fundamentals of Physics, 4th Ed.

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3. Katherine tosses a super ball up against a wall, giving it an initial horizontal and vertical component of velocity of 10 m/s as shown. When the ball hits the wall, the horizontal component of its velocity is reversed; the vertical component is unaffected by the bounce. Oh, and Katherine doesn’t like algebra, so you don’t need to solve this problem algebraically! Use g = 9.8 m/s2.

B) Carefully draw the velocity of the ball immediately before it hits the wall. Kelsey says “hey, you can’t draw the velocity arrow into the wall: the ball isn’t going inside the wall!” Explain why the velocity arrow can point inside the wall, even if the ball doesn’t end up there. What does the velocity vector tell you?

C) Carefully draw the velocity of the ball immediately after it hits the wall.

D) How far back from the wall will the ball hit the ground? Find Δx.

10 m/s

10 m/s

2.0 m

4.0 mΔy

Δx

A) How high up on the wall does the ball hit from the ground? Find Δy.

Not to Scale!

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