Physics · Grades 7–10
Acceleration with opposing forces
Use consistent SI units and keep the stated direction convention.
Rule and assumptions
Use consistent SI units and keep the stated direction convention.
a = (Fright − Fleft)/m
Worked examples
A 6 kg cart has horizontal forces 34 N right and 102 N left. No other horizontal forces act. Taking right as positive, find its acceleration. Round to 3 decimal places if needed. Answer in m/s².
a = (Fright − Fleft)/m (34 − 102) / 6 = -11.333
-11.333 m/s²
A 6 kg cart has horizontal forces 76 N right and 10 N left. No other horizontal forces act. Taking right as positive, find its acceleration. Round to 3 decimal places if needed. Answer in m/s².
a = (Fright − Fleft)/m (76 − 10) / 6 = 11
11 m/s²
Try two questions
A 17 kg cart has horizontal forces 79 N right and 80 N left. No other horizontal forces act. Taking right as positive, find its acceleration. Round to 3 decimal places if needed. Answer in m/s².
A 20 kg cart has horizontal forces 92 N right and 114 N left. No other horizontal forces act. Taking right as positive, find its acceleration. Round to 3 decimal places if needed. Answer in m/s².
Answers and reasoning
Answers and marking notes
- -0.059 m/s²
a = (Fright − Fleft)/m (79 − 80) / 17 = -0.059
- -1.1 m/s²
a = (Fright − Fleft)/m (92 − 114) / 20 = -1.1
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · independent educational and translation review required. Suggested grades are not official curriculum alignment.