Answer:
Vf= 7.29 m/s
Explanation:
Two force act on the object:
1) Gravity
2) Air resistance
Upward motion:
Initial velocity = Vi= 10 m/s
Final velocity = Vf= 0 m/s
Gravity acting downward = g = -9.8 m/s²
Air resistance acting downward = a₁ = - 3 m/s²
Net acceleration = a = -(g + a₁ ) = - ( 9.8 + 3 ) = - 12.8 m/s²
( Acceleration is consider negative if it is in opposite direction of velocity )
Now
2as = Vf² - Vi²
⇒ 2 * (-12.8) *s = 0 - 10²
⇒-25.6 *s = -100
⇒ s = 100/ 25.6
⇒ s = 3.9 m
Downward motion:
Vi= 0 m/s
s = 3.9 m
Gravity acting downward = g = 9.8 m/s²
Air resistance acting upward = a₁ = - 3 m/s²
Net acceleration = a = g - a₁ = 9.8 - 3 = 6.8 m/s²
Now
2as = Vf² - Vi²
⇒ 2 * 6.8 * 3.9 = Vf² - 0
⇒ Vf² = 53. 125
⇒ Vf= 7.29 m/s
Answer:
Resistivity 
It depends upon cross sectional area and length of material
Explanation:
The resistance of any material is given by 
, here 
is the resistivity of material , l is length of material and A is cross sectional area
So resistivity
So resistuivity of any material depends upon area of cross section and length of material
If cross sectional area will be more then resistivity will be more. And is length of the material will be more then resistivity will be less
Answer:
The net friction force is 8.01 N
Explanation:
Net friction force = mass of hockey puck × acceleration
From the equations of motion
v^2 = u^2 + 2as
v = 40 m/s
u = 0 m/s (puck was initially at rest)
s = 30 m
40^2 = 0^2 + 2×a×30
60a = 1600
a = 1600/60 = 26.7 m/s^2
The acceleration of the puck is 26.7 m/s^2
Net friction force = 0.3 × 26.7 = 8.01 N
Answer:
Option B is correct.
Explanation:
Potential energy or chemical potential energy is used to Cook food which is then converted into thermal energy. The type of energy used also depends upon the type of cooking appliances used.
For e.g. stove convert potential energy to thermal energy.
A pot of soup because metal is a better conductor of heat and it stores more heat as well. thermal energy is heat energy.
