Answer:
Friction force always acts tangent to the surface at points of contact. Friction force acts opposite to the direction of motion. There are 2 types of friction: Static friction: If the two surfaces in contact do not move relative to each other, one has static friction.
The mechanical energy of the girl will be conserved because the system is isolated and the initial potential energy will be equal to final kinetic energy.
<h3>
What is the law of conservation of energy?</h3>
The law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.
The change in the potential energy of the launched from a height into the pool without friction from the given height h is calculated by applying the following kinematic equation.
ΔP.E = ΔK.E
where;
- ΔP.E is change in potential energy of the child
- ΔK.E is change in the kinetic energy of the child
mghf - mghi = ¹/₂mv² - ¹/₂mu²
where;
- m is the mass of the girl
- g is acceleration due to gravity
- hi is the initial height of the girl
- hf is the final height when she is launched into the pool
- u is the initial velocity
- v is the final velocity of the girl
Thus, for every closed or isolated system such as this case, mechanical energy is always conserved because the initial potential energy of the girl will be converted into her final kinetic energy.
Learn more about conservation of mechanical energy here: brainly.com/question/332163
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Answer:
0.29713 m/s
Explanation:
m = Mass of person
g = Acceleration due to gravity = 9.81 m/s²
v = Velocity
r = Radius = 18 mm
By balancing the forces in the system we have
The velocity of the coaster is 0.29713 m/s
Low coefficient of friction
1. flying a plane (friction between air and plane)
2. ice skating (friction between ice and skate blade)
3. swimming (water & skin)
4. rowing a boat (water and boat)
The addition of vectors involve both magnitude and direction. In this case, we make use of a triangle to visualize the problem. The length of two sides were given while the measure of the angle between the two sides can be derived. We then assign variables for each of the given quantities.
Let:
b = length of one side = 8 m
c = length of one side = 6 m
A = angle between b and c = 90°-25° = 75°
We then use the cosine law to find the length of the unknown side. The cosine law results to the formula: a^2 = b^2 + c^2 -2*b*c*cos(A). Substituting the values, we then have: a = sqrt[(8)^2 + (6)^2 -2(8)(6)cos(75°)]. Finally, we have a = 8.6691 m.
Next, we make use of the sine law to get the angle, B, which is opposite to the side B. The sine law results to the formula: sin(A)/a = sin(B)/b and consequently, sin(75)/8.6691 = sin(B)/8. We then get B = 63.0464°. However, the direction of the resultant vector is given by the angle Θ which is Θ = 90° - 63.0464° = 26.9536°.
In summary, the resultant vector has a magnitude of 8.6691 m and it makes an angle equal to 26.9536° with the x-axis.
