a the equipment in Figure 1 He used the motor to lift a weight of 2.5 N a height of 2.0 m He measured the speed at which the weight was lifted and calculated the efficiency of the energy transfer. He repeated the experiment to gain two sets of data in his investigation (a) __ (b) Give two reasons for taking repeat readings in an investigation. __ 1.

## Step1: The question is asking about the variables and reasons for repeating an experiment in a scientific investigation. In this case, the student is investigating the efficiency of a motor by lifting a weight and calculating the energy transfer. ## Step2: (a) One variable that the student controlled in his investigation could be the weight of the object being lifted. The weight is mentioned as being in each trial, which means it was kept constant throughout the experiment.### The formula for the work done (energy transferred) by the motor is: ### ### where is the work done, is the force (or weight in this case), and is the distance (or height the weight is lifted). ## Step3: (b) There are several reasons for taking repeat readings in an investigation. Two of these could be: 1. To improve the reliability of the results. By repeating the experiment, the student can check that the results are consistent and not due to random errors or anomalies. 2. To identify and eliminate any potential outliers or anomalous results. If one set of results is significantly different from the others, it may indicate an error in that particular trial.