Answer : The correct option is, (B) Hydrochloric acid(HCl)
Explanation :
Rust is an iron oxide, which is formed by the reaction of iron with oxygen in the presence of water.
As we know that the rust is an iron oxide (base) which is removed by an acid.
As per given options, the acid used to remove the rust from the metal is hydrochloric acid and not sulfuric acid because sulfuric acid is an oxidizing agent which oxidizes the metal more.
While the other options, ammonia and sodium hydroxide are a base.
Hence, hydrochloric acid is used to remove rust from metal.
Answer:
(i) the resistive force exerted by the sand on the bullet is - 1 x 10⁵ N
(ii) the time taken by the bullet to come to rest is 1 x 10⁻⁴ s
Explanation:
Given;
mass of bullet, m = 10 g = 0.01 kg
speed of the bullet, v = 10³ m/s
distance traveled by the bullet, d = 5 cm = 0.05 m
(i) the resistive force exerted by the sand on the bullet
the acceleration of the bullet is given by;
v² = u² + 2as
0 = (10³)² + a(2 x 0.05)
-0.1a = (10⁶)
-a = (10⁶) / 0.1
a = -1 x 10⁷ m/s²
The resistive force is given by;
F = ma
F = (0.01)(-1 x 10⁷)
F = - 1 x 10⁵ N
(ii) the time taken by the bullet to come to rest.
v = u + at
0 = 10³ + (-1 x 10⁷ t)
1 x 10⁷ t = 10³
t = 10³ / 10⁷
t = 1 x 10⁻⁴ s
Work = Force * Distance
Work = 43 * 5 = 215 Joules
Sound waves need a medium to go through and are created through vibrations, whereas light waves need no medium, meaning it can move through space. Light also doesn’t loose energy when reflected, but sound waves get absorbed by the medium they go through causing it to loose energy.
The magnitude of the vector B is 10.9
A vector is a quantity which has magnitude as well as direction and it follows vector laws of addition.
To calculate the magnitude of the vector, we have to put the square of the components of the vector along the axes under the root.
Vector B has components,
x = 2.4
y = 9.8
z = 4.1
Applying the formula,
|B| = √x²+y²+z²
|B| = √(2.4)² + (9.8)² + (4.1)²
|B| = √5.76+96.04+16.81
|B| = √118.61
|B| = 10.9
Talking about the direction the the Vector B, it will be the line joining the origin with the points (2.4,9.8,4.1)
To know more about Vectors, visit,
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