GRAVITATION
BUOYANCY AND FLOATATION
THRUST & PRESSURE
FUNDAMENTAL UNIT OF LIFE
MATTER IN OUR SURROUNDINGS.
100
How does gravitational force change if distance becomes half?
4 Times
100
Define Buoyant force. (Define in terms of weight of displaced fluid.)
Buoyant force is the upward force exerted by a fluid on a body equal to the weight of the fluid displaced by that body.
100
Why is it difficult to hold a school bag with thin straps?
high pressure due to small area
100
Who discovered free-living algae cells in pond water?
Anton van Leeuwenhoek.
100
What is the Kelvin temperature for 27°C and celcius temperature of 350 K.
300.15 K
76.85 oC
200
State the SI unit of G and g.
G=Nm2/kg2 and g= m/s2
200
A cube when reduced in size experiences reduction in buoyant force. Why?
When the cube is reduced in size, its volume decreases.
A smaller volume displaces less fluid when immersed.
Since buoyant force depends on the weight of the fluid displaced, the reduction in displaced fluid leads to a reduction in buoyant force.
200
Longitudinal waves are also called pressure waves — True or False? Justify.
Because the wave travels as successive high-pressure (compressions) and low-pressure (rarefactions) zones, longitudinal waves are also known as pressure waves.
200
Name organelles involved in membrane biogenesis.
smooth endoplasmic reticulum, ribosomes on RER, golgi apparatus
200
Why does steam at 100°C cause more burns than water at 100°C?
Steam at 100°C causes more severe burns than water at 100°C because steam contains additional hidden (latent) heat.
When steam condenses on the skin, it releases latent heat of vaporization, which is a very large amount of energy.
Water at 100°C does not release this extra energy; it only transfers heat due to its temperature.
300
If masses of both bodies become double, how does force change?
4 times
300
A tank 2 m high is half filled with water and half with oil (density 0.60 g/cc). What is the pressure at the bottom?
16000 Pa
300
A girl wearing stilettos applies pressure of 300,000 Pa on the floor. If her weight is 450 N, calculate the area of her heel in contact with the ground.
A=0.0015m2
300
What is ATP called & why? How many ATP does one glucose molecule generate?
ATP is called Adenosine Triphosphate and commonly known as the energy currency of the cell. Because ATP stores energy in its high-energy phosphate bonds and releases energy whenever these bonds are broken.
38 ATP
300
Why does solid CO₂ change directly to gas?
name another chemical that undergoes the same phenomenon.
it undergoes sublimation.
ammonium chloride, napthalene etc
400
Define gravitational potential energy.
The energy acquired by a body by virtue of its position against the gravity.
400
Density of a substance is 2.5 g/cm³. Will it float or sink in water? Justify.
sink. Relative density is greater than 1
400
A hydraulic lift has piston areas 0.1 m² (input) and 1 m² (output). If pressure of 50,000 Pa is applied, calculate:
a) Force applied on small piston
b) Force exerted by large piston
a. 5000 N
b. 50000 N
400
Why is it incorrect to state that mitochondria are fully independent cells?
While mitochondria show some autonomy (their own DNA, ribosomes, and division), they depend on the cell for essential instructions and materials, so they cannot be considered fully independent living cells-SEMI-AUTONOMOUS ORGANELLES
400
Graph shows temperature plateau at B— explain why temperature stays constant.
what is the state of the water at A, C, D and E
Heat supplied → used for change of state (solid → liquid)
Not used to raise temperature → so temperature remains constant
A-Solid, C-Liquid, D-liquid or vapour and E-vapour
500
Why does an object thrown up return to Earth?
due to earth's gravitational pull
500
Which type of plant tissue provides buoyancy?
Aerenchyma
500
A 60 kg man is standing on snow wearing shoes of total sole area 400 cm². If g = 10 m/s², find:
a) Thrust exerted
b) Pressure on snow
a. F= 600 N
b. P = 15000 Pa
500
A cell suddenly stops synthesizing ATP but continues diffusion normally through its membrane.
Identify which transport processes fail and which remain unaffected. Explain why.
Active transport fails.
PROCESS THAT CONTINUE:
Diffusion
Osmosis
Facilitated diffusion
500
Why water feels cooler in an earthen pot than in a metal bucket ?
Water in clay pot feels cooler because evaporation through its pores removes heat, whereas metal has no pores and allows no cooling. also metal is a good conductor of heat and absorbs heat and transfers to water.