Answer:
1.Friction is a catchall word that refers to any force that resists relative tangential motion (or intended motion). "Relative tangential motion" is a fancy way to say "slipping" or "sliding". Its direction is opposite the relative velocity (or intended velocity).
2.Newton’s first law of motion states that a body at rest remains at rest, or, if in motion, remains in motion at a constant velocity unless acted on by a net external force. This is also known as the law of inertia. Inertia is the tendency of an object to remain at rest or remain in motion. Inertia is related to an object’s mass.
Explanation:
The answer is 0 because of the velocity “u” doesn’t A
Answer:
A. 243 N
Explanation:
Friction is the force that opposes the relative motion between systems that are in contact.
This friction force that opposes the motion of the oak chest across the oak surface will be equal and opposite to that exerted by the woman.
First find the normal force which is the force that would point directly upwards to support weight of the block.
Normal force, N= mg where m is the mass of the chest and g is the acceleration due to gravity.
Given m=40 kg and g=9.80 m/s²
N force=40×9.80 =392N
Then find the force of friction which is given by the formula;
<em>F=μN where μ is friction coefficient for the oak chest and N is the normal force on the chest</em>
Given <em>μ</em>=0.620 and N force = 392 N then it will be;
F=0.620× 392 =243.04 N
Answer : 243 N
Efficiency of a simple machine is the ratio of mechanical advantage and speed ratio.
If mechanical advantage = speed ratio then efficiency = 1
Which is impossible for a practical machine due to presence of frictional force which wastes some energy and thus lowers the output