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:
32s
Explanation:
We must establish that by the time the police car catches up to the speeder, both have travelled a certain distance during the same amount of time. However, the police car experiences accelerated motion whereas the speeder travels at a constant velocity. Therefore we will establish two formulas for distance starting with the speeder's distance:
and the police car distance:
Since they both travel the same distance x, we can equal both formulas and solve for t:
Two solutions exist to the equation; the first one being 
The second solution will be:
This result allows us to confirm that the police car will take 32s to catch up to the speeder
Answer:
117.72kW
Explanation:
Given data
Mass m= 50kg
height x = 2m
time taken = 2 minutes= 129 seconds
let us find the work done
WD= force * distance
WD= mgx
WD= 50*9.81*2
WD= 981 Joules
Let us find the power
Power= work * time
Power= 981*120
Power= 117720
Power= 117.72 kW
Hence the power spent is 117.72kW
Answer;
The above statement is false
Explanation;
Symmetrical distribution, commonly known as symmetric distribution or normal distribution, is typically unimodal, meaning it shows only one peak in graph form.
It is a type of distribution where the left side of the distribution mirrors the right side. By definition, a symmetric distribution is never a skewed distribution.
All normal distributions are symmetric and have bell-shaped density curves with a single peak.
Answer:
It can be said to be reliable although it is not valid
Explanation:
This is because Reliability means an indicator of consistency, A measure should produce similar or the same results consistently if it measures the same quantity. So does the thermometer measures over 5days but it is not valid because it deviates from the real value
