Ablock of wood weighing 18 pounds rests on an inclined plane that makes an angle of 60 with the horizontal. how much of the friction force is needed to prevent the block from sliding on the plane?
round answer to nearest whole number. do not use a space or decimal in your answer or it will be marked wrong

Force of friction will be 69 N

Step-by-step explanation:

Given a block of wood weighing 18 pounds rests on an inclined plane that makes an angle of 60 with the horizontal. we have to find the force of friction needed to prevent the block from sliding on the plane.

As the plane makes an inclination, vertical force will act on the wood to slide. Therefore, the friction force must be equal to vertical force so that the wood not to slide.

 where F is friction force, m is weight of an object and is inclination angle made from the horizontal.

As 1 pound=0.453592 kg

∴ 18 lbs = 8.165 kg

         = 8.165 x 9.8 x sin 60°

         = 69.29 N ≈ 69 N  

4444444444444 i think

"it's not the heat, it's the humidity".   that's a partly valid phrase you may have heard in the summer, but it's actually both.   the heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.   this has important considerations for the human body's comfort.   when the body gets too hot, it begins to perspire or sweat to cool itself off.   if the perspiration is not able to evaporate, the body cannot regulate its temperature.   evaporation is a cooling process.   when perspiration is evaporated off the body, it effectively reduces the body's temperature.   when the atmospheric moisture content (i.e. relative humidity) is high, the rate of perspiration from the body decreases.   in other words, the human body feels warmer in humid conditions.   the opposite is true when the relative humidity decreases because the rate of perspiration increases.   the body actually feels cooler in arid conditions.   there is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

step-by-step explanation: