Answer:
Always wear safety goggles when performing an experiment.
Use caution when constructing the track.
Ensure that the track is clear before releasing cars.
Report all accidents to the teacher.Explanation:
Answer:
D. Thomson
Explanation:
The first model of the atom was proposed by J. J. Thomson.
Answer:
a) The maximum contact pressure is 274.58 MPa and the width of contact is 0.058 mm
b) The maximum shear stress is 82.37 MPa at a distance of 0.023 mm
Explanation:
Given data:
L = 20 mm
F = 250 N
r₁ = 10 mm
r₂ = 15 mm
v = 0.3
E = 2.07x10⁵ MPa

a) The maximum contact pressure is:

The width of contact is:

b) According the graph elastic stresses below the surface, for v = 0.3, the maximum shear stress is
T = 0.3*P = 0.3 * 274.58 = 82.37 MPa
At a distance of
0.8*b = 0.8*0.029 = 0.023 mm
Answer:
a) 1200 kN/m²
b) 1,200,000 kg/ms²
c) 1.2 × 10⁹ kg/km.s²
Explanation:
Given:
Pressure = 1200 kPa
a) 1 Pa = 1 N/m²
thus,
1000 N = 1 kN
1200 kPa = 1200 kN/m²
b) 1 Pa = 1 N/m² = 1 kg/ms²
Thus,
1200 kPa = 1200000 Pa
or
1200000 Pa = 1200000 × 1 kg/ms²
or
= 1,200,000 kg/ms²
c) 1 km = 1000 m
or
1 m = 0.001 Km
thus,
1,200,000 kg/ms² =
or
= 1.2 × 10⁹ kg/km.s²