MYP Physics · 20 · structured
A delivery robot starts up a ramp
Independent assessment practice · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- routine
- Marks
- 7
- Topics
- 1
- Answer
- Complete
A 40 kg delivery robot moves up a ramp. Along the ramp, its motors provide 260 N uphill, while friction and rolling resistance together provide 60 N downhill. The component of its weight down the ramp is 120 N.
- a
Represent Describe a correct free-body diagram for the robot.
3 marks - b
Calculate Calculate the resultant force parallel to the ramp and the robot's acceleration.
3 marks - c
Predict Predict the motion if the driving force falls to 150 N while the other forces are unchanged.
1 mark
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a
Represent Describe a correct free-body diagram for the robot.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
Includes the 260 N driving force uphill and the 60 N resistance downhill.
- 2
Includes weight vertically downward and a normal contact force perpendicular to the ramp.
- 3
Does not add a separate ‘force of motion’ or treat the 120 N component as an extra force in addition to weight.
b
Calculate Calculate the resultant force parallel to the ramp and the robot's acceleration.
List the given quantities with units, identify the required quantity, write the governing relationship before substituting, and keep extra digits until the final line so rounding does not distort the result.
- 1
Calculates resultant = 260 − 60 − 120 = 80 N uphill.
- 2
Uses a = F ÷ m.
- 3
Obtains a = 80 ÷ 40 = 2.0 m s⁻² uphill.
c
Predict Predict the motion if the driving force falls to 150 N while the other forces are unchanged.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
The resultant is 30 N downhill, so an upward-moving robot slows; it would later accelerate downhill if the forces remained unchanged.
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