Which of the following is the reason a lever is used in a shovel?
2 answers:
The figure shown below illustrates a lever being used to lift a weight W.
The applied force is F.
In order to lift the weight, the minimum applied force is
F*b = W*a
F = (a/b)W
When the ratio a/b < 1, then the applied force is less than the weight.
The principle behind the use of a lever is to keep the ratio a/b small in order to decrease the effort force.
Answer: A
A lever is used to decrease effort force.
The applied force is F.
In order to lift the weight, the minimum applied force is
F*b = W*a
F = (a/b)W
When the ratio a/b < 1, then the applied force is less than the weight.
The principle behind the use of a lever is to keep the ratio a/b small in order to decrease the effort force.
Answer: A
A lever is used to decrease effort force.
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Draw a diagram to illustrate the problem as shown below.
The vertical component of the launch velocity is
v = (8.5 m/s)*sin30° = 4.25 m/s
The horizontal component of the launch velocity is
8.5*cos30° = 7.361 m/s
Assume that aerodynamic resistance may be ignored.
Because the horizontal distance traveled is 19 m, the time of travel is
t = 19/7.361 = 2.581 s
The downward vertical travel is modeled by
h = (-4.25 m/s)*(2.581 s) + 0.5*(9.8 m/s²)*(2.581 s)²
= 21.675 m
Answer: The height is 21.7 m (nearest tenth)
The vertical component of the launch velocity is
v = (8.5 m/s)*sin30° = 4.25 m/s
The horizontal component of the launch velocity is
8.5*cos30° = 7.361 m/s
Assume that aerodynamic resistance may be ignored.
Because the horizontal distance traveled is 19 m, the time of travel is
t = 19/7.361 = 2.581 s
The downward vertical travel is modeled by
h = (-4.25 m/s)*(2.581 s) + 0.5*(9.8 m/s²)*(2.581 s)²
= 21.675 m
Answer: The height is 21.7 m (nearest tenth)