Answer:

Explanation:
We know that speed is given by dividing distance by time or multiplying length and frequency. The speed of the father will be given by Lf where L is the length of the father’s leg ad f is the frequency.
We know that frequency of simple pendulum follows that 
Now, the speed of the father will be
while for the child the speed will be 
The ratio of the father’s speed to the child’s speed will be

Answer:
As the person moves down the zip wire, her increase in kinetic energy is less than her decrease in gravitational potential energy.
Explanation:
Work is done against the air resistance, causing thermal energy to transfer to the surroundings
Explanation:
It is given that,
Magnetic field, B = 0.1 T
Acceleration, 
Charge on electron,
Mass of electron,
(a) The force acting on the electron when it is accelerated is, F = ma
The force acting on the electron when it is in magnetic field, 
Here, 
So, 
Where
v is the velocity of the electron
B is the magnetic field


v = 341250 m/s
or

So, the speed of the electron is 
(b) In 1 ns, the speed of the electron remains the same as the force is perpendicular to the cross product of velocity and the magnetic field.
Answer:twice of initial value
Explanation:
Given
spring compresses
distance for some initial speed
Suppose v is the initial speed and k be the spring constant
Applying conservation of energy
kinetic energy converted into spring Elastic potential energy

When speed doubles

divide 1 and 2


Therefore spring compresses twice the initial value
<span>θ=0.3sin(4t)
w=0.3cost(4t)(4)=1.2cost(4t)
a=-4.8sin(4t)
cos4t max will always be 1 (refer to cos graph), for same reason, sin4t will always be 0
therefore, wmax=1.2rad/s
vAmax=r*w=250*1.2=300mm/s
(may be different if your picture/radius is from a different picture)
adt=a*r=200*-4.8sin(4t)=0 (sin(4t)=0)
adn=r*w^2=200*1.2^2=288
ad= square root of adt^2+adn^2 = 288mm/s^2</span>