Answer:
Their velocity is 0m/s because the first box was only 10 kg and the second box was double the weight
 
        
             
        
        
        
Answer:
Option B is the correct answer.
Explanation:
  Velocity of a body = Displacement of the body/Time taken
 Displacement and velocity are a vector. Both have direction and magnitude.
 Displacement is generally distance with direction.
 If we divide distance with time taken we will get speed of the airplane. Speed with direction is called velocity. So we need distance between Houston and Dallas, time taken by plane to travel from Houston to Dallas and direction of displacement from Houston to Dallas.
So we need direction.
Option B is the correct answer.
 
        
             
        
        
        
Answer:
Explanation:
For free body diagram see attached sheet .
W is weight of steel girder acting at the middle point of its length . T is tension in the cable .
OB = √ ( 12² - 2² )
= 11.83 m .
OC = 11.83 / 2 = 5.915 m 
Taking moment of tension T and weight W about point O 
W x OC = T x OB 
22 x 5.915 = T x 11.83 
T = 22 x 5.915 / 11.83 
= 11 kN 
Considering forces acting in vertical direction and equating forces in opposite direction 
T + R = W 
R = W - T 
= 22 - 11 = 11 KN 
So force of grinder on the ground = R 
= 11 KN. 
 
        
             
        
        
        
Answer:
W = 289.70 kg
Explanation:
Given data:
Pressure in tank = 23 atm
Altitude 1000 ft
Air temperature  in tank T = 700 F
Volume of tank = 800 ft^3 = 22.654 m^3
from ideal gas equation we have
PV =n RT
Therefore number of mole inside the tank is

               
                
                
we know that 1 mole of air weight is 28.97 g 
therefore, tank air weight is 
                W = 289.70 kg