Answer:
option d and b..............
. . . . . not zero .
Note: "... unbalanced" would be a terrible answer.
Answer:
H = 1/2 g t^2 where t is time to fall a height H
H = 1/8 g T^2 where T is total time in air (2 t = T)
R = V T cos θ horizontal range
3/4 g T^2 = V T cos θ 6 H = R given in problem
cos θ = 3 g T / (4 V) (I)
Now t = V sin θ / g time for projectile to fall from max height
T = 2 V sin θ / g
T / V = 2 sin θ / g
cos θ = 3 g / 4 (T / V) from (I)
cos θ = 3 g / 4 * 2 sin V / g = 6 / 4 sin θ
tan θ = 2/3
θ = 33.7 deg
As a check- let V = 100 m/s
Vx = 100 cos 33.7 = 83,2
Vy = 100 sin 33,7 = 55.5
T = 2 * 55.5 / 9.8 = 11.3 sec
H = 1/2 * 9.8 * (11.3 / 2)^2 = 156
R = 83.2 * 11.3 = 932
R / H = 932 / 156 = 5.97 6 within rounding
Answer:
1. Emma standing on top of mountain
Since she is at the rest position and at some height from the ground so here energy is due to gravitational potential energy
So we have
gravitational potential energy
2. Emma jumping down from mountain top
Due to free fall Emma will start moving with some speed in downwards direction so here we have
motion energy
3. tension in rope at Emma’s lowest position
Due to stretch in the rope here position come to the lowest end and speed comes to zero so whole energy is converted into elastic potential energy
elastic potential energy
4. Emma bouncing back
Due to bouncing back she will again have its kinetic energy with some speed upwards
motion energy