Question

Student's name Jamere Jamison Date keep 3 SIGNIFICANT DİGİTS in answers CIRCLE YOUR ANSWERS in a blue book Put the answers tnumber and units) in this sheet. The sport car can reach a speed of 250 mph. How long would it take to drive across the Brooklyn 1. Bridge (length of 1.8 km) in this car (give answer in seconds)? (Spoints) The distance from Governor's Island to Red Hook is 950 m. If you fired a projectile at the horizontal what velocity would it need in order to make it to the island? (5 points) 35° from 2. You dropped a penny (mass 2.5g) from the top of the building which is 99 m tall. If you measure the penny to have a velocity of 25 m/s just before it hits the ground, how mu work was done to the penny by air resistance? (15 points) 3.

Answer 1

v = 250 mph = 250 times 0.44704 m/s. = 111.76 m/s L = 1.8 km = 1.8 times 1000 m = 1800 m times = distance/velocity = 1800/111.76 = 16.105 s t = 16.105 s 2) R = 950 theta = 35 degree R = u^2 sin 2 thea/h u^2 = 950 times 9.8/sin 70 degree = 950 times 9.8/0.9396 u^2 = 9908.471u = 99.541 m/s 3) T.E at top = P.E = mgh = 2.5 times 10^minus 3 times 9.8 times 9 = 2425.5 times 10^minus 3 2.4255 J. T.E at bottom = KE = 1/2 mv^2 = 1/2 times 2.5 times 10^minus 3 times 25 times 25 = 781.25 times 10^minus 3 = 0.78125 J work done by air resistance = 2.4255 minus 0.78125 w = 1.64425 J