Answer:
v = 719.2 m / s and     a = 83.33 m / s² 
Explanation:
This is a rocket propulsion system where the system is made up of the rocket plus the ejected mass, where the final velocity is
            v - v₀ =  ln (M₀ / M)
 ln (M₀ / M)
where v₀ is the initial velocity, v_{e} the velocity of the gases with respect to the rocket and M₀ and M the initial and final masses of the rocket
In this case, if fuel burns at 75 kg / s, we can calculate the fuel burned for the 10 s
             m_fuel = 75 10
             m_fuel = 750 kg
As the rocket initially had a mass of 3000 kg including 1000 kg of fuel, there are still 250 kg, so the mass of the rocket minus the fuel burned is
               M = 3000 -750 = 2250 kg
let's calculate
             v - 0 = 2500 ln (3000/2250)
             v = 719.2 m / s
To calculate the acceleration, let's use the concept of the rocket thrust, which is the force of the gases on it. In the case of the rocket, it is
              Push = v_{e} dM / dt
let's calculate
              Push = 2500  75
              Push = 187500 N
             If we use Newton's second law
              F = m a
              a = F / m
let's calculate
               a = 187500/2250
               a = 83.33 m / s²
 
        
             
        
        
        
The direction of work.........
        
             
        
        
        
Answer:
Option C is the correct answer.
Explanation:
Considering vertical motion of ball:-
Initial velocity, u =  2 m/s
Acceleration , a = 9.81 m/s²
Displacement, s = 40 m
We have equation of motion s= ut + 0.5 at²
Substituting
    s= ut + 0.5 at²
     40 = 2 x t + 0.5 x 9.81 x t²
    4.9t²  + 2t - 40 = 0
    t = 2.66 s   or t = -3.06 s
 So, time is 2.66 s.
Option C is the correct answer.
 
        
             
        
        
        
The right formula to use for this calculation is the heat capacity formula, 
Heat absorbed, Q = MCT, Where 
M = Mass of the substance = 71
C = Specific heat capacity for iron = 0.450 J/gc
T = Change in temperature = 29 - 11 = 18
Q = 71 * 0.450 *18 = 575.10
The amount of heat absorbed by the iron skillet is 575 J.
        
             
        
        
        
Answer:
Acceleration of the car will be 
Explanation:
We have given mass of the ball m = 1600 kg 
Force in north direction F= 7560 N 
Resistance force which opposes the movement of car 
So net force on the car 
According to second law of motion we know that F=ma
So 
