A 17000 N automobile travels at a speed of 50 km/h northward along a street, and
ID: 2007939 • Letter: A
Question
A 17000 N automobile travels at a speed of 50 km/h northward along a street, and a 7500 N sports car travels at a speed of 65 km/h eastward along an intersecting street.a) If neither driver brakes and the cars collide at the intersection and lock bumpers, what will the magnitude of the velocity of the cars be immediately after the collision? (wants an answer in km/h, NOT m/s)
b) What will the direction of the velocity of the cars be immediately after the collision? (degrees north of east)
I have done this problem probably seven times in the last few days, and I keep getting the same answers, which Mastering Physics tells me are wrong. I've checked an almost identical problem and explanation in my textbook, as well as multiple explanations here on cramster, but so far no luck. :/
Explanation / Answer
a.
v1 = 50 j ;
v2 = 65 i ;
m1 v1 + m2 v2 = ( m1 + m2 ) V ;
17000 ( 50 j ) + 7500 ( 65 i ) = ( 17000 + 7500 ) V ;
V = 34.693 j + 19.897 i ;
magnitude = ( 19.897^2 + 34.693^2 ) = 39.994 km / h
b.
directioin = tan inv ( 34.693 / 19.897 ) = 60.1650 w r t east direction