6 Simple machine (Inclined plane Lever) – Problems and Solutions
1.
Which inclined plane have the same mechanical advantage
A. (1) et (2)
B. (1) et (3)
C. (2) et (3)
D. (2) et (4)
Solution
The inclined plane is one of the simple machines. Simple machines are tools that help people do a job. The inclined plane is used to make it easier for humans to raise an object to a certain height.
The mechanical advantage of the plan incliné is the comparison of the length of the incline to the height of the incline.
The mechanical advantage of the incline plane 1 = 50 cm / 30 cm = 5/3
The mechanical advantage of the incline plane 2 = 5 cm / 4 cm = 5/4
The mechanical advantage of the incline plane 3 = 50 cm / 40 cm = 5/4
The mechanical advantage of the incline plane 4 = 5 cm / 3 cm = 5/3
2.
Distance AB = BC = CD = DE, determine the input force that must be given at point E in order for a balanced lever.
Connu :
AB = BC = CD = DE = l
Distance between output force and fulcrum (a) = l
Distance between input force and fulcrum (b) = 3l
Force de sortie (w) = 900 Newton
Recherché : Forcer (F)
Solution:
The mechanical advantage :
MA = b / a = 3l/l = 3
Magnitude of force :
MA = w / F
F = w / MA
F = 900 Newton / 3
F = 300 Newtons
3.
In order for the lever to be balanced then determine the magnitude of ces input force.
Solution
Determine distance between input force and fulcrum (b)
Connu :
Distance between output force and fulcrum (a) = 25 cm
Force de sortie (w) = 480 Newton
Input force (F) = 160 N
Recherché : Le distance between input force and fulcrum (b)
Solution:
The mechanical advantage :
MA = w / F = 480 N / 160 N = 3
Le distance between input force and fulcrum (b)
MA = b / a
3 = b / 25cm
b = (3)(25 cm)
b = 75cm
Determine magnitude of force (F)
Connu :
Distance between output force and fulcrum (a) = 25 cm – 10 cm = 15 cm
Object’s weight (w) = 480 Newton
Distance between input force and fulcrum (b) = 75 cm
Recherché : Input force (F)
Solution:
Mechanical advantage :
MA = b / a
MA = 75 cm / 15 cm
MA = 5
Magnitude of force (F) :
MA = w / F
F = w / MA
F = 480 Newton / 5
F = 96 Newtons
In order for the lever to be in a balanced position then input force is reduced 64 Newton (160 N – 96 N).
4. The ratio of the lengths of a and b in figure below is a: b = 1: 2.2. The minimum value of force F to lift the object B with weight of 330 Newtons is …. Newton
A. 100
B. 150
C. 2200
D. 7260
Connu :
Distance jusqu'à XNUMX fois output force and fulcrum (a) = 1
Distance between input force and fulcrum (b) = 2.2
Poids (w) = 330 Newton
Recherché : Input force (F)
Solution:
The mechanical advantage of a lever :
MA = w / F = b / a
MA = avantage mécanique, w = weight, F = input force, b = distance between input force and fulcrum, a = distance between output force and fulcrum
w / F = b / une
330 / F = 2.2 / 1
330 / F = 2.2
330 / 2.2 = F
F = 150 Newtons
La bonne réponse est b.
5. A student push an object with a force of F from point A to point B, as shown in figure below. If the frottement between object and boar ignored, determine the mechanical advantage.
A. 4
B. 5 / 3
C. 5 / 4
D. ¾
Connu :
Height of inclined plane (y) = 4 meters – 1 meters = 3 meters
Length of horizontal plane (x) = 4 meters
Voulait: Avantage mécanique (AM)
Solution:
Calculate the length of the inclined plane using the equation of Pythagore :
R = √32+42 = √9+16 = √25 = 5 meters
The mechanical advantage of the inclined plane :
KM = R / y
KM = 5 meters / 3 meters
KM = 5/3
La bonne réponse est b.
6. The mechanical advantage of a lever can be increased by…
A. Shorten the path of the incline
B. enlarge the angle of the incline
C. minimize the angle of the incline
D. reduces the force used to move objects
Solution:
The equation of mechanical advantage of the inclined plane :
Mechanical advantage = length of inclined plane/height of the inclined plane
- The mechanical advantage is directly proportional to the length of the inclined plane and therefore the mechanical advantage is enlarged if the length of the incline is enlarged.
- The mechanical advantage is inversely proportional to the height of the inclined plane, therefore, the mechanical advantage is minimized if the height of the inclined plane is enlarged and the mechanical advantage is enlarged if the height of the incline is reduced.
- If the angle is minimized then the height of the inclined plane is reduced. The mechanical advantage is enlarged if the height of the inclined plane is reduced. Hence if the angle is minimized then the mechanical advantage is enlarged.
If the angle is enlarged then the height of the inclined plane is enlarged. The mechanical advantage is minimized if the height of the inclined plane is enlarged. Hence if the angle is enlarged then the mechanical advantage is minimized.
La bonne réponse est C.
