Laboratory work

Содержание и основные понятия

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Alterna · physics · 4.L
Laboratory work
Laboratory Nos. 10 - 11: lever, slope-plane LAC
Two virtual lab works: lever balance test and slope CPA determination. Do the tests directly in the browser.
GEF · Grade 7
PIF · Baseline
01
Laboratory work No. 10 - Equal leverage
Objective: To verify the F1l1 lever equilibrium rule = F2l2.
Proceedings
Secure lever on the trimmer, balance
Hang the goods with mass m
1
at distance l
1
left of axis
Hang the goods with mass m
2
at distance l
2
right
Get a balance, write F
1
, l
1
, F
2
, l
2
Check: F
1
·l
1
= F
2
·l
2
Repeat for different combinations of weights and shoulders
⚖
Virtual lever — Balance
IV-034L10 · Add goods to both shoulders, balance
LOW PLAYER
Shoulder l1:
20
see
Right-wing aircraft
Shoulder l2:
20
see
Conclusion
The lever rule is confirmed: M1 = M2. The force produced on the shoulder on both sides is equal in equilibrium.
02
Laboratory work No. 11 - Scratch-plane
Objective: To define an inclined plane.
Proceedings
Place the board at an angle, measure height h and length l
Measure the mass of the bar m
Tie down the dynamometer, pull the bar evenly up on the tilt.
Record thrust force F (dynamometer indication)
Calculate: A
Got it.
= mgh, A
morning
= F·l
Compute the AAC: . = A
Got it.
/A
morning
· 100%
Repeat at different inclination angles
📏
Virtual inclined plane — VPD
IV-038L11 · Set the angle and mass, pull the bar up.
Angle α:
30
°
Mass m:
2
kg
Tear μ:
Conclusion
The slope of an inclined plane is always less than 100 per cent. A part of the work is spent overcoming friction. The larger the angle of inclination is the larger the size of the slope (less path, less friction).
That's curious.
The Egyptians built the pyramids 4,500 years ago using tilted planes (rails). Without simple mechanisms, it would not be possible to lift up stones with a mass of 2.5 tons to a height of 146 metres. Physics worked long before it was described.