Speed is v = d/t
Or speed is distance over time
So...
40min / 60min = 0.6667 or 2/3 --> Finding what proportion 40 minutes is to an hour or 60 minutes as we need the units of hours to match up
45km/h = d/0.6667h
d = (45)(0.667)
d = 30.0015 or 30km
Answer:
When you look at a simple koi pond you can find Koi (the secondary consumer) that feeds off of the zooplankton (first consumer), they eat the phytoplankton (producers). All in a simple food chain
Explanation:
Basically, Koi eat the little animal plankton (zooplankton) that then eats the plant plankton (phytoplankton) that can only end when a part of that habitat is removed. If you got rid of the plant plankton then the whole chain would collapse and most likely die.
<span><span>Velocity is a vector, and the initial and final ones are in opposite directions.
There must have been acceleration in order to change the direction of motion.</span>
A) No. The initial and final velocities are the same.
This is all wrong, and not the correct choice.
It's "Yes", and the initial and final velocities are NOT the same.
B) Yes. The ball had to slow down in order to change direction.
This is poor, and not the correct choice.
The "Yes" is correct, but the explanation is bad.
Acceleration does NOT require any change in speed.
C) No. Acceleration is the change in velocity. The ball's velocity is constant.
This is all wrong, and not the correct choice.
It's "Yes", there IS acceleration, and the ball's velocity is NOT constant.
D) Yes. Even though the initial and final velocities are the same, there is a change in direction for the ball.
This choice is misleading too.
The "Yes" is correct ... there IS acceleration.
The change in direction is the reason.
The initial and final velocities are NOT the same. Only the speeds are.
</span>
Answers:
a) 
b) 
Explanation:
a) The centripetal acceleration 
of an object moving in a uniform circular motion is given by the following equation:
Where:
is the angular velocity of the ball
is the radius of the circular motion, which is equal to the length of the string
Then:
This is the centripetal acceleration of the ball
b) On the other hand, in this circular motion there is a force (centripetal force 
) that is directed towards the center and is equal to the tension (
) in the string:
Where 
is the mass of the ball
Hence:
This is the tension in the string
