Brittany is changing the tire of her car on a steep hill 22.4 m high. She stumbles and drops the 10.5-kg spare tire, which rolls
1 answer:
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Answer:
Xcm = 1.95 cm and Ycm = 1.76 cm
Explanation:
The very useful concept of mass center is
R cm = 1/M ∑
Where ri, mi are the mass positions of the bodies from some reference point by selecting and M is the total mass of the body.
Let's look for the total mass
M = m₁ + m₂ + m₃
M = 140 + 45 + 85
M = 270 g
Let's look for the position of each point
Point 1. top vertex, if the triangle has as side d
R₁ = d / 2 i ^ + d j ^
R₁ = (1.7 cm i ^ + 3.4 j ^) cm
Point 2. left vertex. What is the origin of the system?
R₂ = 0
Point 3. Right vertex
R₃ = d i ^
R₃ = 3.4 i ^ cm
a) The x component of the massage center
Xcm = 1 / M (m₁ x₁ + m₂ x₂ + m₃ x₃)
Xcm = 1 / M (m₁ d / 2 + 0 + m₃ d)
Xcm = d / M (m₁ / 2 + m₃)
b) Let's write the mass center component x
Xcm = 1/270 (1.7 140 + 0 + 3.4 85)
Xcm = 238/270
Xcm = 1.95 cm
c) let's find the component and center of mass
Ycm = 1 / M (m₁ y₁ + m₂ y₂ + m₃ y₃)
Ycm = 1 / M (m₁ d + 0 + 0)
Ycm = m₁ / M d
d) let's calculate
Y cm = 1/270 (140 3.4 + 0 + 0)
Ycm = 1.76 cm
Answer:
22.2 W
Explanation:
First of all, we calculate the work done by moving the wagon, using the formula:
where
F = 20 N is the magnitude of the force
d = 1000 m is the displacement of the wagon
is the angle between the direction of the force and of the displacement (assuming the force is applied in the direction of motion)
Substituting, we find
Now we can find the power generated, which is equal to the ratio between the work done and the time taken:
where
W = 20,000 J
t = 15 min = 900 s
Substituting,
And the same value in Joules/second (remember that 1 Watt = 1 Joule/second)