Question 11 Mark
A metal in which even iron can float is:
- Sodium.
- Magnesium.
- Mercury.
- Manganese.
Answer
View full question & answer→- Mercury.
Explanation:
This is because the density of mercury is greater than the iron.
23 questions · timed · auto-graded
A metal in which even iron can float is:
Explanation:
This is because the density of mercury is greater than the iron.
Two objects of different masses falling freely near the surface of moon would:
Explanation:
We know,
v = u + at
⇒ v = 0 + gt
[Here, g is acc. Due to gravity on moon]
Thus, the equation of velocity for a freely falling body is independent of the mass of the body.
So, different masses that are dropped simultaneously with the same or zero initial velocity will have same velocity at any instant.
Consider the following information in respect of four objects A, B, C and D:
| Object | Density (kg/m3) | Volume (m3) | Mass (kg) |
| A | - | 2 | 4000 |
| B | 8000 | 4 | - |
| C | 2000 | - | 1000 |
| D | - | 4 | 2000 |
Which object would float on water?
Explanation:
This is because among these four objects, only the density of object D is less than water.
An object weighs 10N in air. When immersed fully in a liquid, it weighs only 8N. The weight of liquid displaced by the object will be:
Explanation:
We know,
Buoyant force or weight of liquid displaced = Actual weight - Apparent weight
⇒ Weight of the liquid displaced = 10 - 8 = 2 N.
The relative densities of four liquids P, Q, R and S are 1.26, 1.0, 0.84 and 13.6 respectively. An object is floated in all these liquids, one by one. In which liquid the object will float with its maximum volume submerged under the liquid?
Explanation:
This is because R has the lowest density among the four.
Explanation:
At the maximum height 'h', the velocity becomes zero.
Using,
$\text{v}^2 = \mu^2 − 2\text{gh}$
$\Rightarrow 0 =\mu^2 − 2\text{gh}$
$\Rightarrow \text{h}=\frac{\mu^2}{2\text{g}}$
Two particles are placed at some distance from each other. If, keeping the distance between them unchanged, the mass of each of the two particles is doubled, the value of gravitational force between them will become:
$\frac{1}{4}\text{times}$
$\frac{1}{2}\text{times}$
$4\text{ times}$
$2\text{ times}$
Explanation:
Here, m1 and m2 are doubled and r remains constant.
In the relation $\text{F}=\text{G}\times\text{M}\times\frac{\text{m}}{\text{d}^2},$ the quantity G:
Explanation:
This is because G is constant in the given equation.
The force of attraction between two unit point masses separated by a unit distance is called:
he value of g on the surface of the moon:
Explanation:
The value of g on moon is $\frac{1}{6}$ times its value on the earth.
An apple of mass 100g falls from a tree because of gravitational attraction between the earth and the apple. If the magnitude of force exerted by the earth on the apple be F1, and the magnitude of force exerted by the apple on the earth be F2, then:
Explanation:
According to Newton's third law of motion, if an object exerts a force on another object, then the second object exerts an equal and opposite force on the first object.
The value of acceleration due to gravity of earth:
Explanation:
because its value decreases on moving near the equator.
The density of water is 1000kg/m3 and the density of copper is 8900kg/m3. Which of the following statements is incorrect?
$=\frac{\text{The density of a certain volume of copper}}{\text{The density of the same volume of water}}=8.9$
$=\frac{\text{The volume of a certain mass of copper}}{\text{The volume of the same mass of water}}=8.9$
$=\frac{\text{The weight of a certain volume of copper}}{\text{The weight of the same volume of water}}=8.9$
$=\frac{\text{The mass of a certain volume of copper}}{\text{The mass of the same volume of water}}=8.9$
Explanation:
This is because the density is defined as the ratio of the mass of the object to the volume of the object.
The weight of an object at the centre of the earth of radius R is:
Explanation:
because g = 0.
The mass of moon is about 0.012 times that of earth and its diameter is about 0.25 times that of earth. The value of G on the moon will be:
Explanation:
G is universal gravitational constant. So, it remains constant everywhere.
The value of quantity G in the formula for gravitational force:
Explanation:
Because it is a constant in the formula for gravitational force.
The gravitational force of attraction between two objects is x. Keeping the masses of the objects unchanged, if the distance between the objects is halved, then the magnitude of gravitational force between them will become:
$\frac{\text{x}}{4}$
$\frac{\text{x}}{2}$
$2\text{x}$
$4\text{x}$
Explanation:
G = x
m1 and m2 are constant
Since, r is reduced to half, let, $\text{r} =\frac{\text{r}}{2}$
Gravitation force, $\text{F}=\text{G}\times\text{m}_1\times\frac{\text{m}_2}{\text{r}_2} = \text{x}$
When r is reduced to half the force becomes, $\text{F}=\text{G}\times\text{m}_1\times\frac{\text{m}_2}{(\text{r})^2}$
$= \text{G}\times\text{m}_1\times\frac{\text{m}_2}{\Big(\frac{\text{r}}{2}\Big)^2}$
$= 4\text{x}$
According to one of the Kepler's laws of planetary motion:
$\text{r}^2\propto\text{T}^3$
$\text{r}\propto\text{T}^2$
$\text{r}^3\propto\text{T}^2$
$\text{r}^3\propto\frac{1}{\text{T}^2}$
Explanation:
According to Kepler’s third law of planetary motion, the cube of mean distance of a planet from the sun is directly proportional to the square of time it takes to move around the sun.
Four balls, A, B, C and D displace 10mL, 24mL, 15mL and 12mL of a liquid respectively, when immersed completely. The ball which will undergo the maximum apparent loss in weight will be:
Explanation:
This is because B has displaced maximum amount of water.
A rectangular wooden block has length, breadth and height of 50 cm, 25cm and 10cm, respectively. This wooden block is kept on ground in three different ways, turn by turn. Which of the following is the correct statement about the pressure exerted by this block on the ground?
Explanation:
This is because the pressure is inversely proportional to the surface area.
An object is put in three liquids having different densities, one by one. The object floats with $\frac{1}{9},\frac{2}{11}$ and $\frac{3}{7}$ parts of its volume outside the surface of liquids of densities d1, d2 and d3 respectively. Which of the following is the correct order of the densities of the three liquids ?
Explanation:
This is because if the density of the liquid is more than the object, then the object will float on the liquid. The more the object gets immersed in the liquid, lesser is the density of the liquid.
The law of gravitation gives the gravitational force between:
Explanation:
Any two bodies having the same mass.
The atmosphere consisting of a large number of gases is held to the earth by:
Explanation:
Gravity of the earth holds the atmosphere consisting of a large number of gases.