Dan wants to lift his car using a movable pulley system like the one shown in the picture.
Using a movable pulley system will decrease the force needed to lift the car by increasing the
A.
total mass of Dan's body.
B.
strength contained in Dan's arms.
C.
total mass of the car.
D.
distance over which the force is applied.
the answer is d. distance over which the force is applied
21
just took the test its D
To determine the correct answer, we need to understand how a movable pulley system works. In a movable pulley system, the pulley is attached to the object being lifted instead of being fixed to a support structure. The rope or cable passes over the pulley and is attached to a fixed point above. When a force is applied to one end of the rope, the object is lifted.
Now, let's analyze the options:
A. Total mass of Dan's body: The mass of Dan's body has no direct effect on the movable pulley system. It does not increase or decrease the force needed to lift the car. Therefore, this option is incorrect.
B. Strength contained in Dan's arms: The strength in Dan's arms is not directly affected by the movable pulley system. The system will not increase Dan's strength. Therefore, this option is incorrect.
C. Total mass of the car: In a movable pulley system, the total mass of the car does not change. The movable pulley system does not increase or decrease the mass of the car being lifted. Therefore, this option is incorrect.
D. Distance over which the force is applied: The correct answer is D. In a movable pulley system, the force is applied over a greater distance compared to the distance the object is lifted. This allows the force to be spread out over a longer distance, reducing the force needed to lift the object. As a result, using a movable pulley system decreases the force needed to lift the car by increasing the distance over which the force is applied.