Answer: 0.0267m/s
Explanation: Wave speed in m/s
Speed = Distance/Time
Substitute the given values into the formula
Speed = 0.1/3.75
Speed = 0.0267m/s
 
        
             
        
        
        
Answer:
Explanation:
Given
Distance to grandmother's house=100 mi
it is given that during return trip Julie spend equal time driving with speed 30 mph and 70 mph
Let Julie travel x mi with 30 mph and 100-x with 70 mph

x=30 mi
Therefore
Julie's Average speed on the way to Grandmother's house
=42 mph
On return trip

 
        
             
        
        
        
The intensity of the magnetic force F experienced by a charge q moving with speed v in a magnetic field of intensity B is equal to

where 

 is the angle between the directions of v and B.
1) Re-arranging the previous formula, we can calculate the value of the magnetic field intensity. The charge is 

. In this case, v and B are perpendicular, so 

, therefore we have:

2) In this second case, the angle between v and B is 

. The charge is now 

, and the magnetic field is the one we found in the previous part, B=2.8 T, so we can find the intensity of the force experienced by this second charge:
 
 
        
        
        
Answer:
The velocity of the student has after throwing the book is 0.0345 m/s.
Explanation:
Given that,
Mass of book =1.25 kg
Combined mass = 112 kg
Velocity of book = 3.61 m/s
Angle = 31°
We need to calculate the magnitude of the velocity of the student has after throwing the book
Using conservation of momentum along horizontal  direction


Put the value into the formula


Hence, The velocity of the student has after throwing the book is 0.0345 m/s.
 
        
             
        
        
        
Density =mass/Volume 
0.8=mass/60
Mass=0.8*60
Mass=48g