Since there are no external forces, including friction, act on the flatcar. after the sack rests on the flatcar, we would assume that momentum is conserved. This means that
total momentum of car before collision = total momentum of car after collision.
Recall,
momentum = mass x velocity
From the information given,
mass of car before collision = 2000
velocity of car before collision = 3
Thus,
total momentum of car before collision = 2000 x 3 = 6000
Also,
mass of sack = 500
mass of car and sack after collision = 500 + 2000 = 2500
velocity after collision = v
momentum after collision = 2500 x v = 2500v
Since momentum is conserved, then
6000 = 2500v
v = 6000/2500
v = 2.4
the speed of the flatcar is 2.4 m/s
... find length
(way 1) determine acceleration using force
only force act on skier is mg vertically. spilt vector we get force along the incline = mgsin(10) and f= ma so
ma = mgsin(10) or a = gsin(10)
a (along the incline)= gsin(10) = 10sin(10) = 1.74
v^2 = u^2 + 2as
15^2 = 3^2 + 2(1.74)s
s = 62.06 m
(way 2) using conservation of energy
energy (KE+PE) on top = energy at bottom
0.5m3^2 + mgh = 0.5m15^2 +0
h (height of incline) = (112.5 - 4.5)/10 = 19.8 m
length of incline = h/sin(10) = 62.2 m ; trigonometry
... find time
s = (u+v)t/2
t = 2s/(u+v) = 2(62.2)/(3+15) = 6.91 s
Answer:
1keff=1k1+1k2
see further explanation
Explanation:for clarification
Show that the effective force constant of a series combination is given by 1keff=1k1+1k2. (Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination. Also, each spring must exert the same force. Do you see why?
From Hooke's law , we know that the force exerted on an elastic object is directly proportional to the extension provided that the elastic limit is not exceeded.
Now the spring is in series combination
F
e
F=ke
k=f/e.........*
where k is the force constant or the constant of proportionality
k=f/e
............................1
also for effective force constant
divide all through by extension
1) Total force is
Ft=F1+F2
Ft=k1e1+k2e2
F = k(e1+e2) 2)
Since force on the 2 springs is the same, so
k1e1=k2e2
e1=F/k1 and e2=F/k2,
and e1+e2=F/keq
Substituting e1 and e2, you get
1/keq=1/k1+1/k2
Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination.
Answer:
1.10m/s
2.0.1m
3.5Hz
Explanation:
v=velocity, f=frequency and T=wavelength
1.v=ft
v=2x5
=10m
2.v=ft
100=1000T
divide both sides by 1000
T=0.1m
3.v=fT
25=5f
divide both sides by 5
f=5Hz
Answer:
See Explanation
Explanation:
The relationship between angle of an incline and the acceleration of an object moving down the incline.
As the angle of an incline increases, so does the acceleration of the body moving down the incline increases, resolving the force acting on an inclined object
Parallel force = mgsin, perpendicular = mgcosΘ
With th weigh component 'mg' of the parallel force accounting for the acceleration of the body down the incline.
mgsinΘ = ma
Fnet = ma
B.) From Fnet = ma
Fnet = ma
a = Fnet / m
Where Fnet = Net force = mgsinΘ, a = acceleration
