Calculate the mass of an object with a density of 102.5 g/mL and volume of 375 mL.
1 answer:
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Answer:
Assumption: the air resistance on this ball is negligible. Take .
a. The momentum of the ball would be approximately two seconds after it is tossed into the air.
b. The momentum of the ball would be approximately three seconds after it reaches the highest point (assuming that it didn't hit the ground.) This momentum is smaller than zero because it points downwards.
Explanation:
The momentum of an object is equal its mass
times its velocity
. That is:
.
Assume that the air resistance on this ball is negligible. If that's the case, then the ball would accelerate downwards towards the ground at a constant . In other words, its velocity would become approximately
more negative every second.
The initial velocity of the ball is . After two seconds, its velocity would have become
. The momentum of the ball at that time would be around
.
When the ball is at the highest point of its trajectory, the velocity of the ball would be zero. However, the ball would continue to accelerate downwards towards the ground at a constant . That's how the ball's velocity becomes negative.
After three more seconds, the velocity of the ball would be . Accordingly, the ball's momentum at that moment would be
.
Answer:
The trains will collide at a distance 1660 m from the station
Explanation:
Let the train traveling due north with a constant speed of 100 m/s be Train A.
Let the train traveling due south with a constant speed of 136 m/s be Train B.
From the question, Train B leaves a station 2,881 m away (that is 2,881 m away from Train A position).
Hence, the two trains would have traveled a total distance of 2,881 m by the time they collide.
∴ If train A has covered a distance m by the time of collision, then train B would have traveled
m.
Also,
At the position where the trains will collide, the two trains must have traveled for equal time, t.
That is, At the point of collision,
is the time spent by train A
is the time spent by train B
From,
Since the time spent by the two trains is equal,
Then,
m
m
m/s
m/s
Hence,
≅ 1,221 m
This is the distance covered by train A by the time of collision.
Hence, Train B would have covered (2881 - 1221)m = 1660 m
Train B would have covered 1660 m by the time of collision
Since it is train B that leaves a station,
∴ The trains will collide at a distance 1660 m from the station.