Which mutation in a fruit fly could be passed on its offspring? Explain
1 answer:
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Answer:
a)
Explanation:
- A block sliding down an inclined plane, is subject to two external forces along the slide.
- One is the component of gravity (the weight) parallel to the incline.
- If the inclined plane makes an angle θ with the horizontal, this component (projection of the downward gravity along the incline, can be written as follows:
(taking as positive the direction of the movement of the block)
- The other force, is the friction force, that adopts any value needed to meet the Newton's 2nd Law.
- When θ is so large, than the block moves downward along the incline, the friction force can be expressed as follows:
- The normal force, adopts the value needed to prevent any vertical movement through the surface of the incline:
- In equilibrium, both forces, as defined in (1), (2) and (3) must be equal in magnitude, as follows:
- As the block is moving, if the net force is 0, according to Newton's 2nd Law, the block must be moving at constant speed.
- In this condition, the friction coefficient is the kinetic one (μk), which can be calculated as follows:
Answer:
The critical stress required for the propagation of an initial crack = 21.84 M pa
Explanation:
Given data
Modulus of elasticity E = 225 ×
Specific surface energy for magnesium oxide is = 1
Crack length (a) = 0.3 mm = 0.0003 m
Critical stress is given by =
-------- (1)
⇒ 2 E = 2 × 225 ×
× 1 = 450 ×
⇒ a = 3.14 × 0.0003 = 0.000942
⇒ Put these values in equation 1 we get
⇒ =
⇒ = 4.77 ×
⇒ = 2.184 ×
⇒ = 21.84
⇒ = 21.84 M pa
This is the critical stress required for the propagation of an initial crack.