Answer:
θ = 13.16 °
Explanation:
Lets take mass of child = m
Initial velocity ,u= 1.1 m/s
Final velocity ,v=3.7 m/s
d= 22.5 m
The force due to gravity along the incline plane = m g sinθ
The friction force = (m g)/5
Now from work power energy
We know that
 work done by all forces = change in kinetic energy
( m g sinθ - (m g)/5 ) d = 1/2 m v² - 1/2 m u²
(2  g sinθ - ( 2 g)/5 ) d = v² -  u²
take g = 10 m/s²
(20 sinθ - ( 20)/5 ) 22.5 = 3.7² -  1.1²
20 sinθ - 4 =12.48/22.5
θ = 13.16 °
 
        
             
        
        
        
Explanation:
the morning of the birthday party balloon filled with the 2.5 Litre of helium 
 temperature is 294kelvin 
the party starts at the 4 p.m. 
temperature rises 305 Kelvin. 
 the new volume = 4 litre.
At same temperature,
P 
1
 
 V 
2
 
 =P 
2
 
 V 
2
 
 (Boyle's law)
P 
1
 
 =10atm;P 
2
 
 =1atm
V 
1
 
 =4l=V 
2
 
 =8l
But while filling balloons from cylinder when pressure in cylinder becomes 1 atm then further filling is not possible (P 
1
′
 
 =9atm)
Let n be the number of balloons that can be filled.
∴P 
1
′
 
 V 
1
 
 =n(P 
1
 
 V 
1
 
 )
9×8=n(4×1)
n= 
4
9×8
 
 =18balloons
 
        
             
        
        
        
A mix
Explanation:
A battery is an electrochemical cell that converts chemical energy into electrical energy. The chemical reactions in a battery ensures that current is produced. 
- A battery is made up of two electrodes which are the cathode and anode. 
 - The cathode is the positive electrode and the anode is the negative one. 
 - These electrodes are made up of metals. 
 - Electrons moves from the anode to the cathode and current flows from cathode to anode. 
 - At the anode oxidation occurs because electrons are produced here. 
 - It needs to have low electron affinity. 
 - At the cathode where reduction occurs, the electron affinity must be high. 
 - This is the driving force for the production of electricity in electrochemical cells. 
 
Learn more: 
Battery brainly.com/question/8892837
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