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25kg 5 During the Oxford v Cambridge Boat Race, a commentator said, Every crew does the equivalent amount of work of someone who lifts a 2 from the floor to shoulder height. 36 times a minute for 18 minutes. a What total mass is 'lifted by one crew member during the 18-minute Give your answer to 2 significant figures. b A lorry is to be loaded with sacks of potatoes each of mass 25 kg. Work out, correct to 1 significant figure, how long it should take (1) 1 crew member to load 4 tonnes (ii) 8 crew members to load 4 tonnes (iii) 4 crew members to load 4 tonnes (iv) 8 crew members to load 1 tonne It is estimated​

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a) To find the total mass lifted by one crew member during the 18-minute race, we first calculate the total amount of work done by one crew member, and then convert it to mass using the given information.

The work done by one crew member lifting a 2 kg weight 36 times a minute for 18 minutes is:

Work = 2 kg * 36 lifts/minute * 18 minutes

Work = 1296 kg lifts

Now, to find the total mass lifted by one crew member, we divide the total work by the number of lifts:

Total mass lifted = 1296 kg / 36 lifts

Total mass lifted = 36 kg

So, one crew member lifts a total mass of 36 kg during the 18-minute race.

b) Now, let's calculate the time it takes for different scenarios:

(i) 1 crew member to load 4 tonnes:

Time = 4 * 1000 kg / 36 kg

Time = 111.11 minutes ≈ 111 minutes

(ii) 8 crew members to load 4 tonnes:

Time = (4 * 1000 kg) / (36 kg/lift * 8 crew members)

Time = 138.89 minutes ≈ 139 minutes

(iii) 4 crew members to load 4 tonnes:

Time = (4 * 1000 kg) / (36 kg/lift * 4 crew members)

Time = 277.78 minutes ≈ 278 minutes

(iv) 8 crew members to load 1 tonne:

Time = (1 * 1000 kg) / (36 kg/lift * 8 crew members)

Time = 34.72 minutes ≈ 35 minutes

Therefore, the times are approximately:

(i) 111 minutes

(ii) 139 minutes

(iii) 278 minutes

(iv) 35 minutes

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