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23.09.2021 • 

Physics

Pearson VUE - Athena Time Ring 00:35:32
Education 2011
A company produces and tests a new mineral supplement designed to prevent the
common cold. The company tests three dosages of the mineral supplement on
300 participants, male and female between the ages of 25 and 50 over a 6-month
period. Each group has 100 randomly assigned participants. The table shows the
dosages of the mineral supplement given to each participant in each group and
the numbers of participants that report having the common cold during the 6-
month period
Group
Mineral Supplement Study
Number of Common
Dosage
Cold Cases
50 mg/day
10
100 mg/day
6
150 mg/day
5
1
2
3
The company claims that the mineral supplement can effectively prevent the
common cold. A scientist disputes the claim, saying an error exists in the setup of
the groups for the investigation
Which change to the investigation would remove the source of this error?
А.
Test a fourth group, in which participants do not receive the mineral
supplement
B.
Test all three groups, with each participant receiving the mineral
supplement for 12 months
C С
Test only one group, with each participant receiving 200 mg/day of the
mineral supplement
D.
Test only two groups, one with each participant receiving 200 mg/day
and one with 50 mg/day of the mineral supplement
FR

Ответ:

avhobby3

15.03.2022

Physics

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17kN

Explanation:

The force of 10 kN in the cable and the load of 10 kN both have a component along the crane arm.

The force F exerted by the crane arm on the pulley is the sum of these 2 components.

Component of force in cable along the crane arm = 10 cos 30°

Component of load along the crane arm = 10 cos 30°

Considering the forces on the pulley,

F = 10 cos 30° + 10 cos 30°

Force F = 17.32 kN = 17 kN

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