Final answer:
Molly can move Mary in the wagon because the applied force of 300N is greater than the maximum static friction force of 156.8N, which is calculated using Mary's mass and the coefficient of static friction.
Step-by-step explanation:
The question is whether Molly can move Mary in a wagon with a horizontal force of 300N, considering the static friction and Mary's mass of 40kg. The key to solving this is to calculate the maximum force of static friction. The coefficient of static friction (μs) is 0.4, and the force due to gravity (weight) can be found by multiplying Mary's mass by the acceleration due to gravity (9.8 m/s²). The maximum static friction force (μs × normal force) needs to be less than the applied force to ensure movement.
The calculation is: Force of gravity = 40kg × 9.8 m/s² = 392N, and the force of static friction = μs × normal force = 0.4 × 392N = 156.8N.
Since Molly is applying 300N, which is significantly greater than the maximum static friction force of 156.8N, Mary and the wagon will indeed begin to move. This calculation confirms that Molly has applied enough force to overcome the friction between the wagon and the ground, suggesting the wagon will accelerate forward. In conclusion, the force of Molly pushing the wagon can move Mary. Friction, coefficient of static friction, and force of gravity are relevant physics concepts in this scenario.