A projectile has a vertical acceleration of -9.8 m/s² in all its points, and at the highest point in the trajectory his velocity is zero in the vertical direction.
The correct option is C.
Momentum p = mv is conserved.
before: p = 2.5 * 7.5 + 70 * 0
after: p = (2.5 + 70) * v
p before = p after
2.5 * 7.5 = (2.5 + 70) * v
v = 2.5 * 7.0 / (2.5 + 70)
Answer: - 3.43 m/s^2
Explanation:
1) Acceleration = [change in speed] / [time elpased]
2) Change in speed = final speed - initial speed
Since the car comes to a complete stop, the final speed is 0
3) time = 7 seconds
4) Calculation:
acceleration = [ 0 m/s - 24 m/s] / 7 s = - 24 m/s / 7 s = - 3.43 m/s/s or - 3.43 m/s^2
The negative sign means that the car decelerated.
Applying rule of thumb: For every 1000 m, temperature drops by 2 °C. If the ground temperature is room temperature at 20 °C, then:
At 6694 m, temperature = 20 - (6694/1000*2) = 6.6°C
Now,
H= (30t+8000)*ln (C/P), where H = Altitude, t = temperature, C = ground atmospheric pressure, say 101325 Pa, P is the pressure at the altitude.
Therefore,
6694 =(30*6.6+8000) ln (C/P) => 0.8165 = ln (1013255/P) => e^0.8165 = 101325/P => 2.2627 = 101325/P => P = 101325/2.2627 = 44781.39 Pa
