<h2>
Initial velocity of the object = 31.4 m/s</h2>
Explanation:
If an object is thrown downward with an initial velocity of v₀, then the distance it travels is given by s = 4.9 t²+v₀t
Now an object is thrown downward from a cliff 400 m high and it travels 138.3 m in 3 sec. We need to find initial velocity of the object.
s = 4.9 t²+v₀t
138.3 = 4.9 x 3²+ v₀ x 3
3v₀ = 94.2
v₀ = 31.4 m/s
Initial velocity of the object = 31.4 m/s
Answer:
d. to anticipate heat changes
Explanation:
Magnus installs the switch with a bimetal element, so that when the current in the circuit increases above the nominal value, the temperature in the conductor will likewise increase, the bimetal element has the ability to deform when significant temperature changes. In this way it anticipates dangerous current values deforming before and protecting the circuit.
The answer for the following problem is explained below.
Therefore the volume charge density of a substance (ρ) is 0.04 × C.
Explanation:
Given:
radius (r) =2.1 cm = 2.1 × m
height (h) =8.8 cm = 8.8 × m
total charge (q) =6.1× C
To solve:
volume charge density (ρ)
We know;
<u> ρ =q ÷ v</u>
volume of cylinder = π ×r × r × h
volume of cylinder =3.14 × 2.1 × 2.1 × × 8.8 ×
volume of cylinder (v) = 122.23 ×
<u> ρ =q ÷ v</u>
ρ = 6.1× ÷ 122.23 ×
<u>ρ = 0.04 × </u><u> C</u>
Therefore the volume charge density of a substance (ρ) is 0.04 × C.
Use the conservation of angular momentum; angular momentum at the beginning = angular momentum at the end
Conservation of angular momentum:
I1 w1 = I2 w2
Where I is the moment of inertia. For a sphere, I=2/5 m R^2. Substituting into the equation above we get
w2 = I1 w1 / I2 = w1 m1 R1^2 / (m2 R2^2)
w2 = w1 4 * (R1/R2)^2
= 4*(1)*(7E5/7.5)^2
= 3.48E10 revs/(17days)
= 2.04705882 x 10^9 revs/sec
The volume of the room is the product of its dimensions:
Now, from the equation
where d is the density, m is the mass and V is the volume, we deduce
So, multiply the density and the volume to get the mass of air in the room.