Answer:
h = 38.41 m
Explanation:
Given that,
A ball is thrown horizontally from the top of a building and strikes the sidewalk after 2.8 s.
We need to find the height of the building. Let it is h.
Initial speed of the ball, u = 0
Using second equation of motion to find h as follows :

So, the building is 38.41 m tall.
Since speed (v) is in ft/sec, let's convert our diameters from inches to feet:
1) 5/8in = 0.625in
0.625in × 1ft/12in = 0.0521ft
2) 0.25in × 1ft/12in = 0.021ft
Equation:






new velocity coming out of the hose then is
44 ft/sec
Answer:
a) 4 289.8 J
b) 4 289.8 J
c) 6 620.1 N
d) 411 186.3 m/s^2
e) 6 620.1 N
Explanation:
Hi:
a)
The kinetic energy of the bullet is given by the following formula:
K = (1/2) m * v^2
With
m = 16.1 g = 1.61 x 10^-2 kg
v = 730 m/s
K = 4 289.8 J
b)
the work-kinetic energy theorem states that the work done on a system is the same as the differnce in kinetic energy of the same. Since the initial state of the bullet was at zero velocity (it was at rest) Ki = 0, therefore:
W = ΔK = Kf - Ki = 4 289.8 J
c)
The work done by a force is given by the line intergarl of the force along the trayectory of the system (in this case the bullet).
If we consider a constant force (and average net force) directed along the trayectory of the bullet, the work and the force will be realted by:
W = F * L
Where F is the net force and L is the length of the barrel, that is:
F = (4 289.8 J) / (64.8 cm) = (4 289.8 Nm) / (0.648 m) = 6620.1 N
d)
The acceleration can be found dividing the force by the mass:
a = F/m = (6620.1 N) /(16.1 g) = 411 186.3 m/s^2
e)
The force will have a magnitude equal to c) and direction along the barrel towards the exit
Answer:
5365 N
Explanation:
v = Final velocity = 23 m/s
u = Initial velocity = -14 m/s (opposite direction)
m = Mass of ball = 145 g
t = Time taken = 1 ms
Impulse is given by

Impulse is also given by


The magnitude of the average force exerted by the bat on the ball is 5365 N