# Forces 3a

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• Forces 3a
• 1) What is the relationship between friction/air resistance/drag and an object's speed?
• The higher the speed, the more the air resistance increases.
• 2) How does an aircraft with constant thrust move from the ground to constant in the air?
• Part 1) When it takes of, the constant thrust force is higher than the air resistance, so the resultant force is positive, allowing the plane to have a rapid increase of speed and take off.
• Part 2) As the plane speed increases, so does the air resistance, so the increase in speed becomes less.
• Part 3) When the plane is traveling at a steady speed, the forces balance and the resultant force becomes zero. The plane had reached its max speed or terminal velocity.
• 3) Draw, label and explain a velocity time graph showing an object reaching terminal velocity:
• Graph will curve, as the speed increase becomes gradually less, and eventually plateau at terminal velocity.
• 4) What are the two factors that determine the terminal velocity/top speed of a vehicle?
• Shape and material of object.
• 5) describe how a skydiver drops and reaches terminal velocity:
• Part 1) When the skydiver jumps out of the plane, gravity is stronger than air resistance, so the speed increase is large.
• Part 2) As the sky diver's speed increases, so does the air resistance, so the resultant force is less.
• Part 3) eventually the resultant force becomes 0, and the sky diver reaches terminal velocity.
• 6) Recall the definition and units of mass and weight:
• Weight is measured in Newtons, and is the force with which gravity is acting upon an object.
• Mass is the amount of matter in an object, measured in kilograms.
• 7) What is the relationship between weight, mass and gravitational field strength?
• Weight (N)=mass(kg)*gravitational field strength (N/kg)