Answer:
Friction, Gravity, Air Resistance, & Engine
Step-by-step explanation:
Starting a bus requires the application of various types of forces.
1. The first type of force required is the force of friction, which is the force that opposes motion between two surfaces in contact. Friction is necessary to prevent the wheels of the bus from slipping on the road surface when the engine is started.
2. The second type of force required is the force of gravity, which is the force that pulls objects towards the center of the earth. Gravity is necessary to keep the bus on the ground and prevent it from lifting off when the engine is started.
3. The third type of force required is the force of air resistance, which is the force that opposes the motion of an object through the air. Air resistance is necessary to slow down the bus and prevent it from accelerating too quickly when the engine is started.
4. The fourth type of force required is the force of the engine, which is the force that propels the bus forward. The engine force is necessary to overcome the forces of friction, gravity, and air resistance and move the bus forward.