Answer:
the velocity in all the cases will be same.
Explanation:
given,
girl throws a stone from the bridge
air is friction less
we have to find from the given cases in which case the velocity of stone will be greatest.
According to Work energy theorem work done by the sum of all the force is equal to kinetic energy.
As the air is frictionless hence the speed depend upon the height from which the stone is thrown.
height in all the cases is same.
so, the velocity in all the cases will be same.
Answer:
Option (A) is correct.
Explanation:
A horizontal rope has a length of 5 m and a mass of 0.00145 kg. If a pulse occurs on this string, generating a wavelength of 0.6 m and a frequency of 120 Hz. The tension to which the string is subjected is
mass of string, m = 0.00145 kg
Frequency, f = 120 Hz
wavelength = 0.6 m
Speed = frequency x wavelength
speed = 120 x 0.6 = 72 m/s
Let the tension is T.
Use the formula
Option (A) is correct.
Answer:
50 N
Explanation:
Let the natural length of the spring = L
so
100 = k(40 - L) (1)
200 = k(60 - L) (2)
(2)/(1): 2 = (60 - L)/(40 - L)
60 - L = 2(40 - L)
60 - L = 80 - 2L
2L - L = 80 - 60
L = 20
Sub it into (1):
100 = k(40 - 20) = 20k
k = 100/20 = 5 N/in
Now
X = k(30 - L) = 5(30 - 20) = 50 N
Acceleration of the both masses tied together= 6m/s²
Explanation:
The force is given by F= ma
so 5= m1 (8)
m1=0.625 Kg
for m2
5=m2 (24)
m2=0.208 kg
now total mass= m1+m2=0.625+0.208
Total mass=M=0.833 Kg
now F= ma
5= 0.833 (a)
a= 5/0.833
a=6m/s²
