I would say A not 100℅ thou
Energy cannot be created nor be destroyed
Answer:
If I'm not wrong; I think the answer is A
Explanation:
A. Increasing kinetic energy
Answer:
a) frictional force = 93.8 N
b) acceleration = 1.29 ms∧-2
Explanation:
The frictional force can be calculated by :
μ k = Fk / N
where:
- μ k = coefficient of kinetic friction = 0.14
- N= normal force or the force perpendicular to the contacting surface
- Weight of the crate, W = mg = (67 × 10) == 670 N
take acceleration due to gravity = 10m/s∧2
The normal force , N = W = 670N ( upward force equals downward force)
Fk = μ k × N
= 0.14 × 670
Fk = 93.8 N
b) To calculate the magnitude of crate's acceleration
F - Fk = ma
where
- Fk = frictional force = 93.8N
- F = horizontal force = 180 N
- m = mass = 67.0 kg
- a = magnitude of acceleration (unknown)
by substituting,
180 - 93.8 = 67a
86.2 = 67a
acceleration, a = (86.2 ÷ 67)
a = 1.29 ms∧-2
<span>In this situation when using newton's third law, the floor is very rigid and thus when we fall the floor applies
the same amount of force on us with which we were falling on it. The rigidness of the concrete floor makes it difficult for it to absorb some of our force. On the other hand sand is not rigid on impact sine it changes its shape while it absorbs a
large amount of our falling force and a small fraction of this
force is applied on is. That is why we don't get hurt</span>