72km/hr = 72000m/3600seconds(we convert km/hr to m/s
= 20m/s
Velocity= 20m/s
In 4seconds,distance covered=20x4= 80m
Therefore,an accident occurs because in 4seconds, the car would have moved past 20m
Answer:
The ball impact velocity i.e(velocity right before landing) is 6.359 m/s
Explanation:
This problem is related to parabolic motion and can be solved by the following equations:
----------------------(1)
---------(2)
----------------------- (3)
Where:
x = m is the horizontal distance travelled by the golf ball
is the golf ball's initial velocity
is the angle (it was a horizontal shot)
t is the time
y is the final height of the ball
is the initial height of the ball
g is the acceleration due gravity
V is the final velocity of the ball
Step 1: finding t
Let use the equation(2)


s
Substituting (6) in (1):
-------------------(4)
Step 2: Finding
:
From equation(4)


m/s (8)
Substituting
in (3):
v =42 .01 - 15.3566
V=26.359 m/s
Answer:

Yes it is better to pull the rope rather than push it
Explanation:
Let the force is applied at an angle of 60 degree
so we will have net vertical force on the crate is given as

here we know




now friction force on the crate is given as




Yes it is better to pull the rope rather than push it
We have that the electric field at the center of the metal ball due only to the charges on the surface of the metal ball is

From the question we are told that
A solid metal ball of radius 1.5 cm
bearing a charge of -15 nC is located near a hollow plastic ball of radius 1.9 cm bearing
uniformly distributed charge of -7 nC
The distance between the centers of the balls is 9 cm
Generally the equation for the electric field is mathematically given as


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Answer:
2.13 x 10^-19 J or 0.53 eV
Explanation:
cut off wavelength, λo = 700 nm = 700 x 10^-9 m
λ = 400 nm = 400 x 10^-9 m
Use the energy equation

Where, K be the work function



K = 2.13 x 10^-19 J
K = 0.53 eV