Explanation:
Density is defined as the ratio of the mass to the volume. The expression for density is:
The Si unit for density is kg/m³
The dimensional expression for density = [ML⁻³]
Specific volume is defined as the ration of the volume to the mass. It is the reciprocal of density.
The BG unit of specific volume is ft³ / lb.
Answer:
The velocity at impact is 222.2 m/s
Explanation:
The given information are;
The time at which the woman heard the sound of the coin after dropping it into the wishing well = 30 seconds
The average speed of sound in air = 344 m/s
The time in which the dime travel = t₁
The time in which the sound travel = t₂
1/2 × 9.8 × t₁² = 344 × t₂
t₁ + t₂ = 30
4.9·t₁² = 344 × (30 - t₁)
4.9·t₁² + 344·t₁ - 10320 = 0
Which gives -344±
t₁ = 22.676 seconds or -92.9 seconds
Therefore the correct natural time is t₁ = 22.676 seconds
The velocity at impact, v = g×t₁ = 9.8 × 22.676 = 222.2 m/s
The velocity at impact= 222.2 m/s.
Answer: B. 16 times
Explanation:
The mathematic expression for a magnetic force between two magnets is:
(1)
Where:
is a constant
and
are the magnetic charges, which depends on the size of each magnet
is the distance beteween both magnets
As we can see, this force in inversely proportional to the square of the distance. This means that if we increase the distance, the magnetic force will decrease.
Now, if we increase this value by 4 inches from 1 inch:
(2)
(3)
This means the strength of attraction will be 16 times weaker.
Answer:
velocity of truck = 7.32 m/s
velocity of truck = 23.32 m/s
Explanation:
mass of truck, M = 1810 kg
initial velocity of truck, U = 16 m/s
mass of car, m = 673 kg
initial velocity of car, u = 0 m/s
Let the final speed of the car is v and the final speed of truck is V.
Use conservation of momentum
Momentum before collision = Momentum after collision
M x U + m x 0 = M x V + m x v
1810 x 16 + 0 = 1810 V + 673 v
28960 = 1810 V + 673 v .... (1)
As the collision is elastic, so the coefficient of restitution is 1.
By using the formula
where, u1 be the initial velocity of truck, u2 be the initial velocity of the car, v1 be the final velocity of truck and v2 be the final velocity of car.
V - v = - U
V - v = - 16
v - V = 16
v = 16 + V
Substitute in equation (1), we get
28960 = 1810 V + 673 (16 + V)
28960 = 1810 V + 10768 + 673 V
18192 = 2483 V
V = 7.32 m/s
v = 16 + 7.32 = 23.32 m/s
Thus, the velocity of truck after collision is 7.32 m/s and the velocity of car after collision is 23.32 m/s.