Answer:
F = 3750 N
Explanation:
Given that,
Mass of Donny, m = 75 kg
Initial speed, u = 25 m/s
He suddenly slams on the brakes to avoid hitting a squirrel crossing the road, final speed = 0
Time, t = 0.5 s
We need to find the force the seatbelt exert on him. The force is given by :
F = ma
a is acceleration
So, the force is 3750 N.
A good citizen always obeys the law and respects authority.
<span>Coefficient of static friction needs to be 1.1 or larger.
For this problem, we need to static friction to be at least as large as the centripetal acceleration that the car will experience. So let's get our formulas.
Centripetal acceleration:
F = mv^2/r
where
F = force
m = mass
v = velocity
r = radius of curve
Friction
F = mac
where
F = force
m = mass
a = gravitational acceleration
c = coefficient of friction
Since the frictional force has to be at least as large as the Centripetal force, let's set an inequality between them.
mv^2/r ≤ mac
v^2/r ≤ ac
v^2/(ar) ≤ c
Now let's convert km/h to a more convenient m/s.
104 km/h / 3600 s/h * 1000 m/km = 28.88888889 m/s
Let's substitute the known values into the inequality and calculate.
v^2/(ar) ≤ c
(28.88888889 m/s)^2/(9.8 m/s^2 * 78 m) ≤ c
834.5679012 m^2/s^2 / 764.4 m^2/s^2 ≤ c
1.091794743 ≤ c
Rounded to 2 significant figures gives a required coefficient of static friction of 1.1 or greater. This is a rather large value and indicates that the car is not at all likely to be capable of taking that curve at that speed. There are some things that can be done to mitigate the issue. Those being
1. Reduce the velocity.
2. Increase the normal force. Perhaps by aerodynamic means
3. Bank the curve.</span>
Answer:
Vector Quantity
Explanation:
A Vector quantity is a quantity has both magnitude and direction while scalar quantity has only magnitude.
The shoreline is the line where the very tippy tip
of the water stops and the dry sand or dirt starts.
It's the boundary line between water and land.