Let us assume the upstream rowing rate of Alicia = x
Let us assume the downstream rowing rate of Alicia = y
We already know that
Travelling time = Distance traveled/rowing rate
Then
6/(x + 3) = 4/x
6x = 4x + 12
6x - 4x = 12
2x = 12
x = 6
Then
Rowing rate of Alicia going upstream = 6 miles per hour
Rowing rate of Alicia going downstream = 9 miles per hour.
Answer:
Newton
Explanation:
The earth attracts every body towards its centre. The force with which the earth attracts any body towards its centre, is called its weight.
It is a vector quantity.
It always acts towards the centre of earth.
The SI unit of Newton.
Answer:
80% (Eighty percent)
Explanation:
The material has a refractive index (n) of 1.25
Speed of light in a vacuum (c) is 2.99792458 x 10⁸ m/s
We can find the speed of light in the material (v) using the relationship
n = c/v, similarly
v = c/n
therefore v = 2.99792458 x 10⁸ m/s ÷ (1.25) = 239 833 966 m/s
v = 239 833 966 m/s
Therefore the percentage of the speed of light in a vacuum that is the speed of light in the material can be calculated as
(v/c) × 100 = (1/n) × 100 = (1/1.25) × 100 = 0.8 × 100 = 80%
Therefore speed of light in the material (v) is eighty percent of the speed of light in the vacuum (c)
Answer:
0.002925 m
Explanation:
Lt = LO(1 +α Δt ) here Lt is total length Lo is original length α is coefficient of linear expansion and Δt is change in temperature
<h2>for aluminium</h2>
α=25×10^-6
Lt = 5(1+25×10^-6×(70-20))
Lt = 5 (1+25×10^-6×50)
Lt = 5 ( 1+0.00125)
Lt = 5×1.00125
Lt =5.00625 m
<h2>for nickel </h2>
α=13.3×10^-6
Lt =5(1+13.3×10^-6×50)
Lt = 5(1+0.000665)
Lt =5.003325 m
hence difference in length =5.00625-5.003325
= 0.002925 m
Answer:
The final velocity of the bullet is 9 m/s.
Explanation:
We have,
Mass of a bullet is, m = 0.05 kg
Mass of wooden block is, M = 5 kg
Initial speed of bullet, v = 909 m/s
The bullet embeds itself in the block which flies off its stand. Let V is the final velocity of the bullet. The this case, momentum of the system remains conserved. So,
So, the final velocity of the bullet is 9 m/s.
