Physics FUN?

Question

Here is another physics problem... I have answers need help problem solving

A projectile of mass 0.750 kg is shot straight up with an initial velocity of 18.0 m/s. If the projectile rises to a maximum height of only 11.8 m, determine the magnitude of the average force due to air resistance.

Answer 1

Work done by air by using force resisting the motion
F(air)= W(air)/h

W(air)/S=Ke -Pe
W(air)/S=- 0.5mV^2 - mgh

F(air)= 0.5V^2)/h - m(gh
F(air)=0.75( 0.5 (18.0)^2 - 9.81 x 11.8)/ 11.8
F(air)=2.94 N

Answer 2

a motor vehicle starts from relax and speeds up at a persevering with cost in a without delay line. a) interior the 1st 2nd, the motor vehicle covers a distance of two.0 meters. what's the motor vehicle's acceleration? Xi = 0 Vi = 0 at t = a million sec, X = 2 m,... hit upon a x = Vi t + a million/2 a t^2 2 = 0 + a million/2 a (a million)^2 2 = a million/2 a a = 4 m/s^2 b) how lots extra distance will the motor vehicle disguise in the process the 2nd 2nd of its action? Vi = preliminary speed for the 2nd 2nd Vi = Vf1 of the 1st 2nd Vf1 ^ 2 = Vi^2 + 2 a x Vf1 ^ 2 = 0 + 2(4)(2) Vf1 ^ 2 = sixteen Vf1 = 4 m/s then for the 2nd 2nd Vi = 4 m/s X2 = Vi t + a million/2 at^2 X2 = 4(a million) +a million/2 (4)(a million^2) X2 = 4 + 2 X2 = 6 m entire distance coated = X1 + X2 = 2 + 6 = 8 m (nevertheless u didnt ask) the entire distance could be solved (given a=4, and t=2 sec) by potential of X = Vi t + a million/2 a t^2 X = 0 + a million/2 (4)(2)^2 X = 8 m