If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the
1 answer:
You might be interested in
Answer:
40N
Explanation:
Since both weights are connected to one string, you can say that the tensions above each are equal to each other.
If you do the sum of forces for the 4kg mass, then the tension comes out to 40N (if we take gravity to be 10m/s²). But that seemed too good to be true, so I decided to do the work for the 7kg mass as well [which included finding the normal force (N) and plugging it into the sum of forces for the 7kg mass] to find that it also gives 40N as the answer.
If I were to put my process into steps:
- Write out the sum of Forces for both masses
- Set them equal to each other to find normal force (because this is the only unknown)
- Calculate and compare the two tensions to see if they are equal
*This all seems to line up perfectly, but do let me know if my answer doesn't match up with what you might find to he the answer later on.
Total displacement of the car: 405 m
Explanation:
The first part of the motion of the car is a uniformly accelerated motion, so we can use the suvat equation
where:
u = 0 is the initial velocity (the car starts from rest)
is the time elapsed in the 1st part
is the acceleration of the car in the 1st part
is the displacement of the car in the 1st part
Solving for ,
We can also find the velocity of the car after these 20 seconds using the equation:
Now we can find the distance covered by the car in the 2nd part, where it decelerates after having seen the tree limb on the road. We can do it by using the suvat equation:
where:
is the initial velocity at the beginning of the 2nd phase
is the final velocity (the car comes to a stop)
is the time elapsed in the 2nd phase
Substituting,
So, the total displacement of the car is
Learn more about accelerated motion:
#LearnwithBrainly