Answer:
120°
Explanation:
Draw a free body diagram. There are three forces acting on the traffic light. Two tension forces acting along the cables, and weight.
The tension forces have an angle θ between them. That means each tension force forms an angle of θ/2 with respect to the vertical. So the y component of each tension force is:
Ty = T cos (θ/2)
Sum of the forces in the y direction:
∑F = ma
Ty + Ty − W = 0
2 Ty = W
Substituting:
2 T cos (θ/2) = W
If W = T, then:
2 W cos (θ/2) = W
2 cos (θ/2) = 1
cos (θ/2) = 1/2
θ/2 = 60°
θ = 120°
Answer:
Explanation:
The former is the case of constructive interference and the later case relates to destructive interference.
For listener, path difference is the separation of loudspeaker as listener is not standing in between the speaker.
If λ be the wave length
For constructive interference
19 = n λ
For destructive interference
29 = (2n+1) λ / 2
= n λ + λ / 2
= 19 + λ / 2
10 = λ / 2
λ = 20 cm
= 0. 20 m
Motion is the process of changing position.
KE=1/2 mv²
60,500,000 = 1/2 m ( 11,000 m/s )²
60,500,000= 1/2 ( 11,000 )² m
60,500,000= 60,500,000 x m
m= 60,500,000/60,500,000
m= 1 kg
Answer:
C
Explanation:
To melt the alcohol
Heat needed = M . L = 2 . 25 = 50 kcal
To warm up the alcohol
Heat needed = M . sp. ht. . ∆t = 2 . 0.6 . 100 = 120 kcal
Total heat needed = 170 kcal
Assuming that 0.6 kcal/ kg / ˚C is the specific heat and that the answer is wanted in kcal ( a rather odd unit to be in use here.)
