A person pushes horizontally with a force of 180. N on a 67.0 kg crate to move it across a level floor. The coefficient of kinetic friction is 0.14. (a) What is the magnitude of the frictional force? (b) What is the magnitude of the crate's acceleration?

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:

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

by substituting,

180 - 93.8 = 67a

86.2 = 67a

acceleration, a = (86.2 ÷ 67)

a = 1.29 ms∧-2

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.