Answer:
22425 J
Explanation:
From the question,
Applying
Q = cm(t₂-t₁).................. Equation 1
Where Q = Thermal Energy, c = specific heat capacity of aluminium, m = mass of aluminium, t₂ = Final Temperature, t₁ = Initial Temperature.
Given: c = 897 J/kg.K, m = 1.0 kg, t₁ = 50 °C, t₂ = 25 °C (The final temperature is reduced by half)
Substitute these values into equation 1
Q = 897×1×(25-50)
Q = 897×(-25)
Q = -22425 J
Hence the thermal energy lost by the aluminium is 22425 J
 
        
             
        
        
        
Answer:
C. it will not change.
Explanation:
While combing, the rubbing of the comb with the hair, transfer of electron takes place from the hair to the comb and the comb becomes negatively charged. But, this transfer of electron does not make any considerable change in the mass of the hair. This is because the mass of an electron is highly negligible. Now, neglecting the mass of an electron, the transfer of the electrons from the hair to the comb makes charging of the comb, but no loss of mass in the hair. So, the mass of hair will no change.
 
        
             
        
        
        
Answer:5.7m/s
Explanation:
Mass=1kg
Initial velocity=u=8m/s
height=h=1.6m
Final velocity =v
Acceleration due to gravity=g=9.8m/s^2
v^2=u^2-2xgxh
v^2=8^2-2x9.8x1.6
v^2=8x8-2x9.8x1.6
v^2=64-31.36
v^2=32.64
Take the square root of both sides 
√(v^2)=√(32.64)
v=5.7
Speed at the height of 1.6m is 5.7m/s
 
        
             
        
        
        
Answer:
clockwise and counter clockwise
it depends wich way you start paddling
 
        
             
        
        
        
<u>Answer:</u>
According to newton's first law of motion, friction is required to make an object slow down.
<u>Explanation:</u>
According to the Newton's first law of motion, for an object to change its velocity (either a change in the magnitude or the direction), there must be a cause to it which is defined as a net external force.
For example, an object which is sliding across a table or floor slows down due to the net force of friction that is acting on that object.