<span>Taking into account the information above, we know the average mass of the bucket of water may be m=20-5/2=17.5kg. As the bucket of water is pulled at a "constant velocity" the work required to raise the bucket to the platform transformed into the potential energy of the bucket of water. That is why it should be W=mgh=17.5*9.8*40=6860J</span>
Answer:
True
Explanation:
This can be explained by the special theory of relativity for length contraction.
Length contraction is observed in the direction of motion of an object when an object moves with speed closer to the speed of light.
The length of the rocket in this case, appears shorter to the observer on earth in the stationary reference frame which is improper frame whereas the traveler in the rocket is in the same inertial frame which is proper for the rocket's size measurement.
Answer:
To increase kinetic friction, the amount of fine water droplets sprayed before the game is limited.
To reduce kinetic friction. increase the amount of fine water droplets during pregame preparation and sweeping in front of the curling stones.
Explanation:
In curling sports, since the ice sheets are flat, the friction on the stone would be too high and the large smooth stone would not travel half as far. Thus controlling the amount of fine water droplets sprayed before the game is limited pregame is necessary to increase friction.
On the other hand, reducing ice kinetic friction involves two ways. The first way is adding bumps to the ice which is known as pebbling. Fine water droplets are sprayed onto the flat ice surface. These droplets freeze into small "pebbles", which the curling stones "ride" on as they slide down the ice. This increases contact pressure which lowers the friction of the stone with the ice. As a result, the stones travel farther, and curl less.
The second way to reduce the kinetic friction is sweeping in front of the large smooth stone. The sweeping action quickly heats and melts the pebbles on the ice leaving a film of water. This film reduces the friction between the stone and ice.
Answer:
Her real salary has fallen and her nominal salary has risen. The correct option is C
Explanation:
NOMINAL SALARY is defined as the actual amount of money paid to a worker as compensation for work done monthly.
REAL SALARY or wages is defined as the quantity of goods and services an individual can purchase from a monthly income. Therefore it is affected by an increase or decrease in the general price level in an economy( inflation). For instance, if an individual nominal wage is increased by 10% and inflation is 0%( that is, there was no increase in price of goods in the market) then the individuals real wage is increased by 10% too. But if inflation is 10%, then the real wage will be 0% ( meaning the inflation is rising at the same rate with the nominal wage increase).
In the case of the professor, she had $200 increase in her monthly nominal wage and she can buy fewer number of goods and services than she bought last year(increased inflation). Therefore her real salary has fallen because even with the $200 increase, she couldn't buy her usual quantity of goods.
