Answer:
μ = 0.0315
Explanation:
Since the car moves on a horizontal surface, if we sum forces equal to zero on the Y-axis, we can determine the value of the normal force exerted by the ground on the vehicle. This force is equal to the weight of the cart (product of its mass by gravity)
N = m*g (1)
The friction force is equal to the product of the normal force by the coefficient of friction.
F = μ*N (2)
This way replacing 1 in 2, we have:
F = μ*m*g (2)
Using the theorem of work and energy, which tells us that the sum of the potential and kinetic energies and the work done on a body is equal to the final kinetic energy of the body. We can determine an equation that relates the frictional force to the initial speed of the carriage, so we will determine the coefficient of friction.
where:
vf = final velocity = 0
vi = initial velocity = 85 [km/h] = 23.61 [m/s]
d = displacement = 900 [m]
F = friction force [N]
The final velocity is zero since when the vehicle has traveled 900 meters its velocity is zero.
Now replacing:
(1/2)*m*(23.61)^2 = μ*m*g*d
0.5*(23.61)^2 = μ*9,81*900
μ = 0.0315
The correct answer to the question is unbalanced .
EXPLANATION:
As per Newton's first laws of motion, we know that a body at rest will be at rest or a body moving with uniform velocity along a straight line will keep on moving with the same velocity along that line unless and until it is compelled by some external unbalanced forces acting on.
Hence, it is the unbalanced force which is responsible for creating the motion on the body.
As per the question, Anne applied some force on the toy car. It is called applied force. There is also frictional force between car and the surface which opposes the motion of the car. The toy car will move due to the net force acting on it. The net force is known as unbalanced force.
Answer:
No
Explanation:
The vertical component of Jack's initial velocity is:
5.0
⋅
sin
30
∘
=
5.0
⋅
1
2
=
2.5
m/s
With gravitational acceleration
9.8
m/s
2
, he will reach the highest point of his trajectory after:
2.5
9.8
≈
0.255
s
The average vertical component of his velocity in that
0.255
s
will be:
1
2
⋅
2.5
=
1.25
m/s
So the highest point of his trajectory will be:
0.255
⋅
1.25
≈
0.32
m
So he will pass approximately
7
cm
above the top of the candle.
The horizontal component of his velocity will be a constant:
5.0
⋅
cos
30
∘
=
5.0
⋅
√
3
2
≈
4.33
m/s
So Jack's trajectory will be substantially longer than it is high and he will spend little time anywhere near above the candle.
Answer:
.
Explanation:
The average speed of an object is equal to total distance over total time.
- Distance traveled:
.
How much time is taken? This trip is divided into two halves, each of distance 
.
Time spent on the first half of the trip:
.
Similarly, time spent on the second half of the trip:
.
In total:
.
Average speed:
.
This value turned out to be slightly different from the average of the speed during the two halves of the journey. The reason is that the object traveled at each speed for a different amount of time. It spent more time at the slower speed, which gives that speed a greater weight in the average. That explains why the average speed is closer to 
rather than 
.
D. 980, this is the best answer because 35 x 7 is 980 :)
