Answer:
v_f = 3 m/s
Explanation:
From work energy theorem;
W = K_f - K_i
Where;
K_f is final kinetic energy
K_i is initial kinetic energy
W is work done
K_f = ½mv_f²
K_i = ½mv_i²
Where v_f and v_i are final and initial velocities respectively
Thus;
W = ½mv_f² - ½mv_i²
We are given;
W = 150 J
m = 60 kg
v_i = 2 m/s
Thus;
150 = ½×60(v_f² - 2²)
150 = 30(v_f² - 4)
(v_f² - 4) = 150/30
(v_f² - 4) = 5
v_f² = 5 + 4
v_f² = 9
v_f = √9
v_f = 3 m/s
Answer:
u = 13.67 m/s
Explanation:
given,
window height = 2 m
window is 7.5 m off the ground on its path up
total distance from the ground to pass the window = 2 + 7.5 = 9.5 m
time taken to go past the window = 1.30 s
using equation of motion



u = 13.67 m/s
hence, the initial velocity of the ball is equal to 13.67 m/s
If the wavelength increases (gets longer), then the frequency <em>decreases</em>.
(A wave occurs less often.)
Answer:
.
Explanation:
The average speed of an object is equal to total distance over total time.
- Distance traveled:
.
How much time is taken? This trip is divided into two halves, each of distance
.
Time spent on the first half of the trip:
.
Similarly, time spent on the second half of the trip:
.
In total:
.
Average speed:
.
This value turned out to be slightly different from the average of the speed during the two halves of the journey. The reason is that the object traveled at each speed for a different amount of time. It spent more time at the slower speed, which gives that speed a greater weight in the average. That explains why the average speed is closer to
rather than
.
Answer:
alkaline earth metals
Group 2 metals, the alkaline earth metals, have 2 valence electrons, and thus form M2+ ions. The halogens, Group 17 , reach a full valence shell upon reduction, and thus form X− ions
Explanation: