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3 years ago

A soccer player kicks a ball with a speed of 30 m/s at an angle of 10. How long does the ball stay in the air?

1 answer:

4 0

"10" is not a very satisfying description of an angle.
I'll assume it's 10 degrees, and that it's the angle of the initial trajectory
above the horizontal.

The vertical component of the ball's speed is 30 sin(10°) = 5.209 meters per second.

The acceleration of gravity is 9.8 meters per second² downward.

The ball continues to rise for 9.8/5.209 = 1.881 seconds after the kick.
At that time, it reaches the peak of its arc, and if nobody else has contacted it yet,
it begins to fall, and takes the same length of time to return to the ground whence
it was kicked.

So the time between the kick and return to the ground is (2 x 1.881) = <u>3.763 seconds</u>.

Note: As is customary and necessary at the high school level,
we assume no air resistance.

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Susan, driving north at 53 mphmph , and Shawn, driving east at 63 mphmph , are approaching an intersection. Part A What is Shawn

mafiozo [28]

Answer:

Shawn's speed relative to Susan's speed = 10 mph

Resultant velocity = 82.32 mph

Explanation:

The given data :-

i) Susan driving in north and speed of Susan is ( v₁ ) = 53 mph.

ii) Shawn driving in east and speed of Shawn is ( v₂ ) = 63 mph.

iii) The speed of both Susan and Shawn is relative to earth.

iv) The angle between Susan in north and Shawn in east is 90°.

We have to find Shawn's speed relative to Susan's speed.

v₂₁ = v₂ - v₁ = 63 - 53 = 10 mph

Resultant velocity,

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v = 82.32 mph

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3 years ago

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