Answer:
Explanation:
Well, lets say you park your car on the top of a hill, gravitational energy prevents it from the car falling back. Or a snow pack, aka before a potential avalanche. Though gravity cannot keep it safe forever, gravitational energy keeps it from crashing asap. In this case, it gives you time to escape. Altogether, gravitational force keeps the earth in it's atmosphere.
This is just testing your ability to recall that kinetic energy is given by:
<span>k.e. = ½mv² </span>
<span>where m is the mass and v is the velocity of the particle. </span>
<span>The frequency of the light is redundant information. </span>
<span>Here, you are given m = 9.1 * 10^-31 kg and v = 7.00 * 10^5 m/s. </span>
<span>Just plug in the values: </span>
<span>k.e. = ½ * 9.1 * 10^-31 * (7.00 * 10^5)² </span>
<span>k.e. = 2.23 * 10^-19 J
so it will be d:2.2*10^-19 J</span>
Answer:
Explanation:
Remark
This is a second class lever. It is much more efficient than the fishing pole problem. All distances are measured from the pivot in these kinds of questions.
Givens
d1 = 1.5
d2 = ?
m1 = 50 kg
m2 = 30 kg
The lighter child will have to sit further away from the pivot to make the two conditions equal.
Formula
d1*m1 = d2*m2
1.5*50 = d2 * 30
75 = 30 * d2
75/30 = d2
d2 = 2.5
Remark
Notice that the distance is longer for the lighter child. The fact that these are masses and not forces does not matter, but you should take note of it. There is a difference between masses and forces. See the fishing pole problem.
Answer to the multiple Choice question. No motion on this kind of problem means equal moments. The answer is D
Problem 2
1) The wheels are further apart making B more stable. The wider the distance the wheels are apart, the harder it would be to tip the concrete mixer over
2) The center of gravity is lower. The higher the force is the more chance you have of exerting an external force to tip the mixer over.
The normal force acting on the object is 500 N in the upward direction
<u>Explanation:</u>
As George is applying a downward force, the normal force will be in the upward direction. The normal force will be exerted due to the acceleration due to gravity exerted on the object.
So, as per Newton's second law, the normal force acting on the object can be measured by the product of mass of the object and the acceleration due to gravity acting on the object.
But as the acceleration due to gravity is a downward acting acceleration and the normal force is a upward acting force, so the acceleration will be having a negative sign in the formula.
Here, acceleration due to gravity g = -10 m/s² and mass is given as 50 kg, then
Normal force = 50 × (-10) = -500 N
So, the normal force acting on the object is 500 N in the upward direction.
