a. d1 = 3.65-1.55 = 2.10 m. = Distance the shield must travel.
V^2 = Vo^2 + 2g*d2 = 0.
2g*d2 = -Vo^2, d2 = -Vo^2/2g = -(7.4)^2/-19.6 = 2.79 m. Yes.
b. V^2 = 7.4^2 - 19.6*2.10 = 13.6, V = 3.69 m/s.
7.4 - 3.69 = 3.71 = Change in speed.
c. V^2 = 7.4^2 + 19.6*2.1 = 95.92, V = 9.79 m/s.
9.79-7.4 = 2.39 m/s = The change in speed.
d. No.
e. When the shield is moving upward, the force of gravity decreases the speed. When the shield is moving downward, the force of gravity increases the speed.
Totally confused on this question, Please help.
1)In the movie The avengers, Captain America sees an alien speeder incoming. The speeder passes directly overhead at 3.65m. If he throws his shield straight up with a speed of 7.40 m/s from a height of 1.55 m above the ground (a) will the shied reach the speeder? (b) if so, what velocity? If not, what initial speed must it have to reach the speeder? (c) Find the change in speed of the shield if it were thrown straight down from the speeder to 1.55 m with an initial speed of 7.40 m/s. (d) Does the change in speed of the downward-moving shield agree with the magnitude of the speed change of the shield moving upward between the same elevations? (e) Explain physically why it does or does not agree.
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