Final answer:
The normal force the ground exerts on the mower can be approximated by the mower's weight, which is calculated as the product of its mass (50 kg) and the acceleration due to gravity (9.8 m/s²), resulting in a normal force of approximately 490 N.
Step-by-step explanation:
To determine the magnitude of the normal force the ground exerts on the mower, it is essential to consider two forces. First, the weight of the mower due to gravity (W = m * g, where m is the mass and g is the acceleration due to gravity which is approximately 9.8 m/s²). Second, the vertical component of the pushing force, which can be calculated using trigonometry (F_y = F * sin(θ), where F is the pushing force and θ is the angle).
If the mower is moving at a constant speed and the yard is level, then the net vertical force is zero, meaning the normal force (N) must counteract both the weight of the mower and the vertical component of the push. Since the exact pushing force (F) is not given, and assuming there's no upward acceleration, the normal force can be primarily attributed to the weight of the mower. Therefore, N ≈ m * g. For a 50 kg mower, N ≈ 50 kg * 9.8 m/s² = 490 N.