Answer:
Explanation:
mass of box, m = 60 kg
distance, d = 6.2 m
force, P = 150 N
coefficient of kinetic friction, μk = 0.21
work done by the gravitational force, Wg = Force x distance x cos 90
Wg = 0 J
Work done by the normal force, Wn = force x distance x Cos 90
Wn = 0 J
Work done by the friction force, Wf = - μk mg d
Wf = - 0.21 x 60 x 9.8 x 6.2 = - 765.58 J
Work done by the applied force, Wp = P x d
Wp = 150 x 6.2 = 930 J
Answer:
C. a dense region of positive charge existed somewhere in the atom.
Explanation:
Physicist Ernest Rutherford created the gold foil experiment in which he shot a beam of alpha particles at a sheet of gold foil, which then sent a few of the particles flying after they were deflected. Based on the information gathered after completing this experiment, Rutherford concluded that a dense region of positive charge existed somewhere in the atom.
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Answer:
(A) The correct answer is option (B) three halves that of the old unit.
(B) The answer is three fourth that of old unit
Explanation:
from the relation;
(A) Fromthe expression;
K = Qd/AΔT
Anew = 3/2 A(old)
(B)
K¹ = 2K(old), so we get
A(old) = A(old)/2
Combining with part A, we have;
Anew = 3/2 *A(old)/2
= 3/4A(old)
The answer is three fourth that of old unit
One reason is that when you have been out in the cold, your hands feet and exposed features of your face will take time to recover as the blood circulation improves and supplied warm blood to capillaries. So the relatively warm room you enter will not immediately feel warm until the blood has regained its normal circulation. Other factors are that windows are cooled from the outside and condensation forms on the inside because of moisture in the air. For this condensation to evaporate requires heat, which will be extracted from the room and the air near the windows will be cooled. The cold air will descend and form a draught at floor level and this will tend to make the room cooler.
