Question

A boy is exerting a force of 70 n at a 50-degree angle on a lawn mower. He is accelerating at 1. 8 m/s2. Round the answers to the nearest whole number. What is the mass of the lawn mower? kg what is the normal force exerted on the lawn mower? n.

Answer 1

• mass: 25.0 kg
• normal force: (boy, 53.6 N), (gravity, 245 N), (total, 298.6 N)

Step-by-step explanation:

Assuming the 50° angle is measured with respect to the horizontal, the force resolves into the (horizontal, vertical) components:

f = (70 N)(cos(50°), sin(50°)) ≈ (44.995, 53.623) N

In the horizontal direction, ...

f = ma

m = f/a = (44.995 N)/(1.8 m/s^2) = 24.997 kg

The mass of the lawnmower is about 25.0 kg.

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In the vertical direction, the force exerted by the boy is about 53.6 N. That is added to the force due to gravity, which is (25.0 kg)(9.8 m/s^2) ≈ 245.

The total normal force on the lawnmower is 53.6 N +245 N = 298.6 N.