Answer:
The pressure exerted by the woman on the floor is 1.9061 x 10⁷ N/m²
Explanation:
Given;
mass of the woman, m = 55 kg
diameter of the circular heel, d = 6.0 mm
radius of the heel, r = 3.0 mm = 0.003 m
Cross-sectional area of the heel is given by;
A = πr²
A = π(0.003)²
A = 2.8278 x 10⁻⁵ m²
The weight of the woman is given by;
W = mg
W = 55 x 9.8
W = 539 N
The pressure exerted by the woman on the floor is given by;
P = F / A
P = W / A
P = 539 / (2.8278 x 10⁻⁵ )
P = 1.9061 x 10⁷ N/m²
Therefore, the pressure exerted by the woman on the floor is 1.9061 x 10⁷ N/m²
Answer:
The lid becomes tighter
It becomes tighter because metals have a lower heat capacity than glass meaning their temperature drops (or increases) much faster than glass for the same energy change. So in this example, the metal will contract faster than the glass causing it to be more tighter around the glass.
Answer:
148(m/s)
Explanation:
V_final = V_current + (acceleration) x (time)
= 4 + 80 x 1.8 = 148 (m/s)
Answer:
Maximum horizontal distance covered by both the stones will be same because the speed at which both the stones are thrown is same.
However, stone that is thrown upward will spend more time in the air as compared to the stone that is thrown downward because of the projectile and vertical component of the velocity.
Answer:
Microwave: Radiation
Water: Conduction, convection & radiation.
Explanation:
- When we heat a food using microwave then the water content of the food is only heated by the microwave.
- Microwaves make the molecules of water vibrate frequently with a frequency closer to the frequency of microwaves and this increases the kinetic energy of the molecules which produces heat in the water molecules this heat then propagates to the whole food by conduction and convection, but the heat enters the food only via radiation.
Now when the food item is kept into warm water then the molecules closer to the food heat the food by conduction through direct energy transfer by lattice vibrations and when they become cooler than the mass of water all around then due to density difference they settle down and their place is occupied by warmer molecules around in the fluid leading to convection.
Radiation of energy from a mass occurs continuously irrespective of the medium present there. So the heat of water also enters the food by radiation of energy from the water molecules.
