According to Newton;s Second Law of motion, F = ma. Acceleration is the change of velocity per unit time. Since there is no change of velocity, then acceleration is equal to zero. Consequently, the net force F is also equal to zero. The net force is equal to the sum of all the forces acting on the body. These forces are the horizontal force and the frictional force. They are acting in opposite directions. So, the sum must be
F = 0 = Horizontal - Frictional
0 = 100 N - Frictional
Frictional force = 100 N
The element is a resistor, so some of the electrical energy flowing through the heating element is converted to thermal energy.
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<span>Using conservation of energy and momentum you can solve this question. M_l = mass of linebacker
M_ h = mass of halfback
V_l = velocity of linebacker
V_h = velocity of halfback
So for conservation of momentum,
rho = mv
M_l x V_li + M_h x V_hi = M_l x V_lf + M_h x V_hf
For conservation of energy (kinetic)
E_k = 1/2mv^2/ 1/2mV_li^2 + 1/2mV_{hi}^2 = 1/2mV_{lf}^2 + 1/2mV_{hf}^2
Where i and h stand for initial and final values.
We are already told the masses, \[M_l = 110kg\] \[M_h = 85kg\] and the final velocities \[V_{fi} = 8.5ms^{-1}\] and \[V_{ih} = 7.2ms^{-1} </span>