V= s/t
=
5.15/ 350
=68.0 km/h
Answer:
Vy = 26 m/s sin 30 = 13 m/s vertical speed
t = Vy / a = 13 m/s / 9.80 m/s^2 = 1.33 sec time to reach Vy = 0
H = Vy t + 1/2 g t^2
H = 13 m/s * 1.33 sec - 1.33^2 * 9.8 / 2 m = 8.62 m
Momentum is a vector, although we don't hammer on that. In order to completely describe a momentum, you need a magnitude AND a direction ... just like force and velocity.
So choice #2 is the magnitude of a momentum, without its direction.
<em>Choice #3</em> is the full package, with both the magnitude and the direction.
Choice #1 has units of energy, and choice #4 has units of acceleration, so neither of those can be it.
Answer:
3.2 m/s
Explanation:
Given:
Δx = 1000 m
v₀ = 23 m/s
a = -0.26 m/s²
t = 76 s
Find: v
This problem is over-defined. We only need 3 pieces of information, and we're given 4. There are several equations we can use. For example:
v = at + v₀
v = (-0.26 m/s²) (76 s) + (23 m/s)
v = 3.2 m/s
Or:
Δx = ½ (v + v₀) t
(1000 m) = ½ (v + 23 m/s) (76 s)
v = 3.3 m/s
Or:
v² = v₀² + 2aΔx
v² = (23 m/s)² + 2(-0.26 m/s²)(1000 m)
v = 3.0 m/s
Or:
Δx = vt − ½ at²
(1000 m) = v (76 s) − ½ (-0.26 m/s²) (76 s)²
v = 3.3 m/s
As you can see, you get slightly different answers depending on which variables you use. Since 1000 m has 1 significant figure, compared to the other variables which have 2 significant figures, I recommend using the first equation.
