Final answer:
Work done by friction on a 124 g toy coming to a halt is calculated using the work-energy principle and is found to be -0.5957 joules, with the negative sign indicating work done against the motion.
Step-by-step explanation:
To calculate the work done by friction on the 124 g toy as it comes to a halt, we can apply the work-energy principle, which states that the work done is equal to the change in kinetic energy of the object. The toy starts with some initial kinetic energy and ends with zero kinetic energy when it stops. The mass of the toy must be in kilograms for calculations, so we convert 124 g to 0.124 kg.
The initial kinetic energy (KEi) of the toy is given by the formula:
KEi = 1/2 m * v²
Where m is the mass of the toy and v is the initial speed.
Plugging in the values, we get:
KEi = 1/2 * 0.124 kg * (3.1 m/s)² = 0.5957 J
The final kinetic energy (KEf) of the toy is zero since it comes to a halt. The work done by friction (Wf) is equal to the negative change in kinetic energy.
Wf = KEf - KEi = 0 - 0.5957 J = -0.5957 J
Therefore, the work done by friction on the toy is -0.5957 joules. The negative sign indicates that the friction force does work against the direction of the toy's motion.