Problem 11. An airport has a moving walkway in a long corridor (of length L) des
ID: 1327152 • Letter: P
Question
Problem 11. An airport has a moving walkway in a long corridor (of length L) designed to save passengers time. If Tom walks through the corridor (not on the moving walkway), it takes him 150 s to reach the far end. If Tom stands on the moving walkway, it takes him loo s to reach the far end. How long would it take Tom to reach the far end if he got on the moving walkway and walked at his normal speed relative to the walkway itself? Note that the answer does not depend on the length L (which is given only as a variable, not as a specific number) Problem 12. A projectile is fired from a point A at an angle above the horizontal. At its highest point after traveling a horizontal distance D, it explodes into two identical pieces that travel horizontally with equal but opposite velocities as measured relative to the projectile just before it exploded. If one fragment lands back at point A, how far from A (in terms of D) is the second fragment?Explanation / Answer
d=distance,
t=time,
r=rate,
rt=d,distance
150r=100
(100/150=.66)
r=.66 feet/second
100r=100
(100/100=1)
r=1 feet/second
combined rate= 0.66+1 = 1.66 feet/second
1.66t=100
(100/1.66=60.24)
t=60.24 seconds
2)Consider the the two smaller masses m and the mass before explosion was 2m
thus momentum at the moment of explosion is 2mV .So after the explosion one mass comes back to A retracing its original path so it must have a velocity -V and consider its momentum is -mV
So let us take Momentum is conserved so the total must still be 2mV
2mV = -mV + XmV. So X can be calculated as
X= 3 so the second fragment must have velocity 3V
The highest point is the halfway point of the trajectory
Consider there were no explosion the mass would have travel led another distance D for a total of 2D
but it is going 3 times as fast so it will go another 3D
So the total distance is 3D+D=4D