<h2>
Hello!</h2>
The answer is:
The kinetic energy of the object is equal to 85 J.
<h2>
Why?</h2>
The kinetic energy involves the speed and the mass of an object in motion. We can calculate the following the work needed to speed an object (kinetic energy) using the equation:
Where,
m, is the mas of the object
v, is the speed of the object.
Now, we are given:
So, substituting and calculating the kinetic energy of the object, we have:
We have that the kinetic energy of the object is equal to 85 J.
Have a nice day!
Answer:
A. The force exerted by the sprinter must be 9.6 × 10² N.
B. The force that propels the sprinter is exerted by the blocks.
Explanation:
Hi there!
Let´s begin with part B:
The sprinter exerts a force on the blocks and, as a reaction, the blocks exert a force on the sprinter that is of equal magnitude but opposite direction (Newton´s third law). This reaction of the blocks causes the acceleration of the sprinter.
Part A
The force exerted by the blocks can be calculated using Newton´s second law:
F = m · a
Where:
F = exerted force.
m = mass of the object being accelerated.
a = acceleration of the object after applying the force on the object.
F = m · a
F = 64 kg · 15 m/s²
F = 9.6 × 10² N
Because you have to have energy to have work.
Answer:
B. A car of mass 2000 kg with speed 7 m/s
Explanation:
The kinetic energy of an object is given by:
where m is the mass of the object and v is its speed.
From the formula, we see that the larger the mass and the speed of the object, the larger its kinetic energy. Among the choices given, we see that the car with largest mass and largest speed is car B, which has a mass of 2000 kg and speed of 7 m/s. Its kinetic energy is:
We can verify that the other cars have smaller kinetic energy. In fact:
- Car A: 
- Car C: 
- Car D: 
So, car B is the one which has most kinetic energy.
Its B , Lizabeth thinks Miss Lottie and her marigolds are strange, and her frustration with her own life drives Lizabeth to destroy the women's flowers.
