A dairy farmer notices that a circular water trough near the barn has become rusty and now has a hole near the base. The hole is
1 answer:
You might be interested in
The first thing you should know is that the distance is equal to the speed per time.
Therefore if You walk forward at 1.5 m / s for 8s
d = 1.5t [0,8] s
Your friend decides to walk faster and starts at 2.0 m / s for the first 4 s.
d = 2t [0,4] s
Then she slows down and walks forward at 1.0 m / s for the next 4s
d = t + 4 [4,8] s
Who walked farther?
They both walked the same distance
12 meters
Therefore if You walk forward at 1.5 m / s for 8s
d = 1.5t [0,8] s
Your friend decides to walk faster and starts at 2.0 m / s for the first 4 s.
d = 2t [0,4] s
Then she slows down and walks forward at 1.0 m / s for the next 4s
d = t + 4 [4,8] s
Who walked farther?
They both walked the same distance
12 meters
Answer:
Approximately (assuming that air resistance is negligible.)
Explanation:
Let denote the initial velocity of this ball. Let
denote the angle of elevation of that velocity.
The initial velocity of this ball could be decomposed into two parts:
- Initial vertical velocity:
.
- Initial horizontal velocity:
.
If air resistance on this ball is negligible, alone would be sufficient for finding the time of flight of this ball.
Calculate given that
and
:
.
Assume that air resistance on this ball is zero. Right before the ball hits the ground, the vertical velocity of this ball would be exactly the opposite of the value when the ball was launched.
Since , the vertical velocity of this ball right before landing would be
.
Calculate the change to the vertical velocity of this ball:
.
In other words, the vertical velocity of this ball should have change by during the entire flight (from the launch to the landing.)
The question states that the gravitational field strength on this ball is . In other words, the (vertical) downward gravitational pull on this ball could change the vertical velocity of the ball by
each second. What fraction of a second would it take to change the vertical velocity of this ball by
?
.
In other words, it would take to change the velocity of this ball from the initial velocity at launch to the final velocity at landing. Therefore, the time of the flight of this ball would be
.