Speed and velocity have the same magnitudes. The only difference is that speed is a scalar quantity and velocity is a vector quantity. In other words, speed is just a magnitude, while velocity is a magnitude with direction. They're essentially the same.
Let's convert miles to meters and minutes to seconds
1/4 mile = 402.34 meters ( 1 mile = 1609 m)
13.1 minutes = 786 seconds (1 minute = 60 seconds)
Speed is calculated as distance over time, thus,
Speed = (402.34 meters)*8/786 seconds
a.) Speed = 4.1 m./s
b.) Velocity = 4.1 m/s
        
             
        
        
        
The tension has to hold the part of the weight in the direction of the string:
T = mg*cos(theta)
Theta=0, whole weight, theta=90, T=0, if the pendulum is horizontal, the string will be loose! Yeah
        
                    
             
        
        
        
Answer:
density = 5520 kg/m^3
Explanation:
given that
radius of earth = 6378 km
G = 6.67 x 10⁻¹¹ m³/kg.s²
g = 9.80 m/s²
we know,

mass of earth 


M = 5.972 x 10²⁴ kg
density =
V = volume of the earth = 4/3πr³
V = 4/3 x 3.14 x (6378  x 10³)³
V = 1.08 x 10²¹ m³
density = 
density = 5.52 x 10³  kg/m^3
density = 5520 kg/m^3
 
        
             
        
        
        
This problem is to let you practice using Newton's second law of motion:
Force = (mass) x (acceleration)
-- The airplane's mass when it takes off (before it burns any of its load of fuel) is 320,000 kg.
-- The force available is (240,000 N/per engine) x (4 engines) = 960,000 N. 
-- Now you know ' F ' and ' mass '.  Use Newton's second law of motion to calculate the plane's acceleration.
 
        
             
        
        
        
Capacitance is a measure of charge stored per volt.