Question

Devon has several toy car bodies and motors. The motors have the same mass, but they provide different amounts of force, as shown in this table.

A 2 column table with 2 rows. Column 1 is labeled Motor with entries 1, 2. Column 2 is labeled Force (N) with entries 10, 15.

The bodies have the masses shown in this table.

A 2 column table with 2 rows. Column 1 is labeled Body with entries 1, 2. Column 2 is labeled Mass (kilograms) with entries 0.2, 0.6.

Which motor and body should Devon use to build the car with the greatest acceleration?

motor 1, with body 1
motor 1, with body 2
motor 2, with body 1
motor 2, with body 2

Answer 1

Motor 2 with body 1.

Reason: acceleration a = F/(m_motor + m_body). The motors have the same mass, so pick the largest force (15 N) and the smallest body mass (0.2 kg) to maximize a.