Answer:
1920Joules
Explanation:
The formula for calculating the kinetic energy of a body is expressed as;
KE = 1/2 mv²
m isthe mass
V is the speed
For the two masses, the combined KE is expressed as;
KE = 1/2(m1+m2)v²
KE = 1/2(45+15)(8)²
KE = 1/2 * 60 * 64
KE = 30 * 64
KE = 1920J
Hence the combined kinetic energy of the boy and the bicycle is 1920Joules
With each<span> passing </span>day<span>, the </span>high tides occur<span> about an </span>hour later<span>. The moon rises about an </span>hour later each day<span>, too (actually, 54 minutes </span>later<span>). Since the moon pulls up the </span>tides<span>, these two delays are connected. As the earth rotates through </span>one day<span>, the moon moves in its orbit.</span>
Answer:
B object at rest
Explanation:
object at rest means it wouldn't be moving, like a parked car or sleeping person therefore, B is the correct answer
The appropriate expression for the calculation of power by relating the angular energy in a given time.
In other words the instantaneous power of an angular accelerating body is the torque times the angular velocity

Where
Torque
Angular speed
Our values are given by


The angular velocity must be transformed into radians per second then


Replacing,



The average power delivered by the engine at this rotation rate is 211.1kW
Answer : Use a magnet to pull out the iron filings as they are attracted to a magnet
Explanation : we use the magnet to separate the sand from the iron filing. Because the magnet has an attraction power.
We can say that we can use the magnet to attract the iron filings out of the mixture because iron is magnetic solid, but sand will not attract because sand is not magnetic solid.
So, we use a magnet to pull out the iron filings as they are attracted to a magnet.