Batteries always use direct current. That eliminates A and C. The other part of the answers is just asking what direct/alternating means. Alternating currents change directions moving one way then another. Direct current only moves in one direction. Therefore, the answer is D, since the current is direct and direct currents move in one direction.
Answer:
hub9hybygbgybgybgygybsbgydgbydxbgbyxdgbyxdyggdxygbyxdgybzgbydbgyzsbgydgbyzdgxbybgydzs
Explanation:
The frictional force of an object is the product of the normal force and coefficient of kinetic friction. Here the frictional force acting on the object is 16.4 N.
<h3>What is frictional force?</h3>
Frictional force is a kind of force acting on a body to resist it from motion. Thus, the direction of the force will be in negative with the magnitude. Frictional force is the product of coefficient of friction and the normal force.
The normal force acting on the object of mass 4.2 Kg is N = mg
N = 4.2 Kg × 9.8 m/s² = 41.16 N
Frictional force = ц N
= 0.40 × 41.16 N
= 16.4 N.
Therefore, the frictional force acting between the surface of the object and the floor is 16.4 N
To find more on frictional force, refer here:
brainly.com/question/1714663
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Your question is incomplete. But your complete question probably was:
The coefficient of kinetic friction between an object and the surface upon which it is sliding is 0.40 the weight of the object is 4.2 kg. What is the frictional force of the object?
Answer:
A) 
B) 
C) 
D) mosquitoes speed in part B is very much larger than that of part C.
Explanation:
Given:
- Distance form the sound source,
- sound intensity level at the given location,
- diameter of the eardrum membrane in humans,
- We have the minimum detectable intensity to the human ears,
(A)
<u>Now the intensity of the sound at the given location is related mathematically as:</u>
..........................................(1)
<em>As we know :</em>
is the energy transferred to the eardrums per second.
(B)
mass of mosquito, 
<u>Now the velocity of mosquito for the same kinetic energy:</u>
(C)
Given:
- Sound intensity,
<u>Using eq. (1)</u>
Now, power:
Hence:
(D)
mosquitoes speed in part B is very much larger than that of part C.
