Answer:
a) One
Explanation:
In a uniform circular motion there must be a force acting to keep it in the circular track. This force can either be centripetal or a centrifugal force.
According to the Newton's first law of motion a particle continues to be in state of rest or in uniform motion until acted upon by an external force.
Here the term uniform motion need to be understood which refers to the uniform velocity of the particle in accordance to the vector laws.
The average speed can be easily calculated by taking the
ratio of distance and time. That is:
average speed = distance / time
so calculating:
average speed = 4875 ft / 6.85 minutes
<span>average speed = 711.68 ft / min</span>
Answer:
Explanation:
The pail is rotated at a constant rate in vertical circular path so it has the minimum speed at all points along its circular path . That means at top position the velocity is almost zero. In that case the centripetal force at top position will be provided by its weight or
mg = mv² / r ( r is radius of vertical circular path )
v = √ rg
At the bottom position its velocity will be increased due to loss of potential energy
so 1/2 m V² = 1/2 m v² + mg x 2r
V =√ 5 gr
If R be the reaction force at the bottom by bottom of pail
R - mg = mV² / r
R = mg +mV² / r
= mg + m x 5gr / r
R = 6mg
This is the magnitude of the force exerted by the water on the bottom of the pail .
1000 kcal because you only get 10% of the energy of the thing you eat
