Answer:
b. Friction decreased when he went from pavement to ice and then increased two more times.
Explanation:
Frictional force depends on the normal force of the surface and a friction coefficient.

Since we're talking about the same car, the value of
will remain constant whereas μ will represent the change in the frictional coefficient of the surface. Now we consider the different surfaces, cars will slide in an icy road which means that the frictional coefficient is smaller than the pavement.
After Joshua returns to the pavement road, the resulting frictional force increases and will do so one more time when he reaches the gravel road. Gravel roads have greater frictional coefficients than pavement roads which means the frictional force will increase a second time.
Answer:
<u><em>1000 units for breakeven</em></u>
Explanation:
Let x be the number of units sold at breakeven.
The total sales at the point would be $2x.
Variable costs would be $1x and fixed costs are $1000.
Total costs are = $1x + $1000
At breakeven: Sales = Costs
Sales =m Costs
$2x = $1x + $1000
$1x = $1000
x = 1000 units.
At 1000 units the sales are equal to the costs ("breakeven").
Answer: W = 294 J
Explanation: Solution:
Work is expressed as the product of force and the distance of the object.
W = Fd where F = mg
W= Fd
= mg d
= 15 kg ( 9.8 m/s²) ( 2m )
= 294 J
X- rays. It can damage living tissue