Answer:
The minimum power neccesary is:
Explanation:
The water is bring to a boil so it goes from 25°C to 100°C, the temperature rise si:
Considering that the cup is always at the same temperatura as the water the trasfered energy can be calculated as:
We have that:
So:
Given that this energy was supplied in 2 minutes:
The minimum power neccesary is:
Answer:
The average speed of the earth in its orbit is
Explanation:
The average distance between the Earth and the Sun is .
The average speed of the earth in its orbit can be found by the next equation :
(1)
Where r is the radius and T is the period.
In this case, the orbit of the Earth can be considered as a circle
() instead of an ellipse.
It takes 1 year to the Earth to make one revolution around the Sun. Therefore, its period will be 365.25 days.
Notice that to express the period in terms of seconds, the following is needed:
⇒
Then, equation 1 can be used:
Answer:
(A) Impulse will be 1.116 kgm/sec
(B) Force will be equal to 1116 N
Explanation:
We have given mass of the basketball m = 0.120 kg
Initial speed of the ball
Final speed of the ball
(A) Impulse delivered by the ball is equal to the change in momentum
So impulse will be equal to
So impulse will be 1.116 kgm/sec
(B) Time is given for which force is exerted
We know that impulse is equal to
F = 1116 N
The second Newton's law of motion states that the rate of change in momentum of a moving body is proportional to the resultant force.
Therefore, to understand this law one must understand the concept of momentum and that a body in motion experiences force.
As far as momentum is concerned it is important to note that as a body moves the momentum changes with change in time and also that a body at rest has 0 momentum because its speed/velocity is zero.
It is this change in momentum with time that is proportional to the resultant force experienced by the body.
(25 km/day) x (1000 m/km) x (day/86,400sec) = 0.29 meter/sec.
That's a gentle, graceful landing.