Answer:
A. 80 N
Explanation:
Since the uniform plank is pivoted at its center at an angle of 30 to the vertical, then it is 90° - 30° = 60° to the horizontal.
Let L be the length of the plank = 4 m, the perpendicular distance of the 4 kg mass form the pivot point is Lcos60°/2. Then the moment of the 4 kg mass about its pivot point is mgLcos60/2 where m = mass = 4 kg and g = acceleration due to gravity = 10 m/s²
Let F be the force applied at 0.5 m from the pivot point. The perpendicular distance of F from the pivot point is 0.5cos60°. Thus the moment of this force about the pivot point is F × 0.5cos60° = 0.5Fcos60°
Since both moments are the same for equilibrium,
mgLcos60/2 = 0.5Fcos60°
F = mgL/(2 × 0.5 m)
F = 4 kg × 10 m/s² × 4 m/1 m
F = 80 kgm/s²
F = 80 N
Answer:
The fore-brain consists of the cerebrum, thalamus, and hypothalamus. Mid-brain relays information between fore-brain and hind-brain. Mid-brain plays important role in developing motor functions like eye movement, auditory functions and visual processing. The crus cerebri connects the cerebral hemispheres to the cerebellum, contains a portion having a network of neurons that is responsible for arousal and alertness.
Answer:
conduction- toughing a stove and getting burnt
Explanation:
convection-hot air rising cooling and falling radiation-heat from the sun warming your face
Not only do ferromagnetic materials respond strongly to magnets (the way iron is attracted to magnets), they can also be magnetized themselves—that is, they can be induced to become magnetic or made into permanent magnets. ... In an unmagnetized ferromagnetic object, domains are small and randomly oriented.
The complementary base pair is:
TTC, CTG, AGT, CTA.