Answer:
v = 15 m / s
Explanation:
In this exercise we are given the position function
x = 5 t²
and we are asked for the average velocity in an interval between t = 0 and t= 3 s, which is defined by the displacement between the time interval
let's look for the displacements
t = 0 x₀ = 0 m
t = 3 
= 5 3 2
x_{f} = 45 m
we substitute
v = 15 m / s
Answer:
a) t = 4.14 s
b) Speed with which it hits the ground = 40.58 m/s
Explanation:
Using the equations of motion,
g = 9.8 m/s², y = H = 84 m,
Initial velocity, u = 0 m/s,
final velocity, v = ?
Total Time of fall, t = ?
a) y = ut + gt²/2
84 = 0 + 9.8t²/2
4.9t² = 84
t² = 84/4.9
t = 4.14 s
b) v = u + gt
v = 0 + (9.8 × 4.14)
v = 40.58 m/s
Using the equation;
TE = 1/2mv^2(1+2); where k = 2/5 for a solid sphere; V is the velocity, and m is the mass.
Total energy = 0.5 × 21 × 8² (7/5)
= 940.8 J
The rotational kinetic energy of the sphere is 940.8 J
1000 miles = 1 609 340 m
2 weeks = 1209 600 s
v = 1609340/1209600 = 1.33 m/s
