The only vertical forces are weight and normal force, and they balance since the surface is horizontal. The horizontal forces are the applied force (uppercase F) in the direction the block slides and the frictional force (lowercase f) in the opposite direction.
Apply Newton's 2nd Law in the horizontal direction:
ΣF = ma
F - f = ma
where f = µmg
F - µmg = ma
F = m(a +µg)
F = (20 kg)(1.4 m/s² + 0.28(9.8 m/s²)
F = 83 N
Explanation:
Initial energy = final energy + work done by friction
PE = PE + KE + W
mgH = mgh + 1/2 mv² + W
(800)(9.8)(30) = (800)(9.8)(2) + 1/2 (800) v² + 25000
v = 22.1 m/s
Without friction:
PE = PE + KE
mgH = mgh + 1/2 mv²
(800)(9.8)(30) = (800)(9.8)(2) + 1/2 (800) v²
v = 23.4 m/s
The answer is option B "anaerobic." Weightlifting deals with stress to the muscles when lifting weights and due time the muscles will begin to adapt and get stronger. Other examples of anaerobic exercise are things like: weight training, sprinting, cycling, and jumping anything that has short exertion, and high-intensity movement is an anaerobic exercise.
Hope this helps!
Nonportrit
<span>The economy is based upon the production of oil. Saudi Arabi is one of the leading oil producing countries in the world. It is one of the founding counties of Opec, an oil cartel made up of middle eastern oil producing countries which try to manipulate the worldwide price of oil.</span>
Answer:
X-rays go all the way through the body, but ultraviolet rays do not.
Explanation:
An x-ray will show inside the body, but uv light isn't strong enough to go all the way through the body.
