2) A lift in a shopping centre can transport 20 people to a height of 54 m in a time of 14 s. The lift compartment has a mass of 1420 kg and the average person has a mass of 60 kg.
Calculate the combined mass of the compartment and the 20 people in it.
b Calculate the energy gained as the lift travels upwards.
a
Think about the lift as it rises. Which form of energy is increasing?
с
Calculate the rate at which energy is transferred by the lift motor to the compartment.

Do social recommendations increase ad effectiveness? a study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. the results are given below.correctly recalled the brandarrival 409153browsing20484b. conduct the hypothesis test, using the 0.025 level of significance.what is the value of the test statistic? χ2stat=what is the p-value? p-value=is this value significant atα=0.025?