Answer:
The shortest distance in which you can stop the automobile by locking the brakes is 53.64 m
Explanation:
Given;
coefficient of kinetic friction, μ = 0.84
speed of the automobile, u = 29.0 m/s
To determine the the shortest distance in which you can stop an automobile by locking the brakes, we apply the following equation;
v² = u² + 2ax
where;
v is the final velocity
u is the initial velocity
a is the acceleration
x is the shortest distance
First we determine a;
From Newton's second law of motion
∑F = ma
F is the kinetic friction that opposes the motion of the car
-Fk = ma
but, -Fk = -μN
-μN = ma
-μmg = ma
-μg = a
- 0.8 x 9.8 = a
-7.84 m/s² = a
Now, substitute in the value of a in the equation above
v² = u² + 2ax
when the automobile stops, the final velocity, v = 0
0 = 29² + 2(-7.84)x
0 = 841 - 15.68x
15.68x = 841
x = 841 / 15.68
x = 53.64 m
Thus, the shortest distance in which you can stop the automobile by locking the brakes is 53.64 m
Answer:
C.Vacuum
Explanation:
There are three methods of transfer of heat:
1) Conduction: conduction is the transfer of heat by direct contact between the molecules of two objects (or two substances). The particles of the hotter object vibrate faster than the particles of the colder object, so energy is transferred by collisions of the molecules from the hotter object to the colder object.
2) Convection: convection is the transfer of heat by mass movement of molecules. This occurs in fluids (liquids or gases), when an external source of heat is applied to the fluid. As a result, the part of the fluid closer to the source gets warmer, so it becomes less dense and rises, while the colder part sinks and replaces the hotter part, forming a convective current. The process continues until the heat source is removed.
3) Radiation: radiation is the transfer of heat carried by electromagnetic waves. Electromagnetic waves can travel in any medium and in a vacuum, so they are the only type of heat transfer that can occur in a vacuum (while conduction and convection cannot occur in a vacuum).
I calculated on a sheet and used differentiation to solve the problems.
