A student is given an assignment to demonstrate diffraction. He takes a photograph of a straw in a glass of water. The straw app
2 answers:
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Answer:
a) The swimmer should travel perpendicular to the bank to minimize the spent in getting to the other side.
b) 133.33 m
c) 53.13°
d) 106.67 m
Explanation:
a) The swimmer should travel perpendicular to the bank to minimize the spent in getting to the other side.
b) velocity = distance * time
Let the velocity of the swimmer be = 1.5 m/s
The separation of the two sides of the river, d = 80 m
The time taken by the swimmer to get to the other end of the river bank,
t = 80/1.5
t = 53.33 s
The swimmer will be carried downstream by the river through a distance, s
Let the velocity of the river be = 2.5 m/s
S = 53.33 * 2.5
S = 133.33 m
c) To minimize the distance traveled by the swimmer, his resultant velocity must be perpendicular to the velocity of the swimmer relative to water
That is ,
d) Downstream velocity of the swimmer,
The vertical displacement is given by,
80 = 1.2 t
t = 80/1.2
t = 66.67 s
the horizontal speed,
The downstream horizontal distance of the swimmer,
x = 1.6 * 66.67
x = 106.67 m
Answer:
C) 3,000 kg m/s
Explanation:
We can consider the horizontal velocity of the motorcycle to be zero, since it rolls off the edge of the cliff very slowly. So, we only need to find the vertical velocity at the time of the impact with the ground.
The vertical velocity of the motorcycle at time t is given by (free-fall motion):
where
is the initial vertical velocity (zero, since the motorcycle is not moving)
g = 9.8 m/s^2 is the acceleration due to gravity
t is the time
Since the motorcycle hits the ground after t = 3 seconds, we have
And since we know its mass, m=100 kg, we can find its momentum:
and the negative sign simply means downward direction.