Answer:
The initial velocity was U=22.14m/s
Explanation:
Step one :
Applying the third equation of motion
v² = u²+ 2as
Where v= Final velocity
U =initial velocity
a= acceleration due to gravity
S= distance or displacement
Step two :
V= 0
a= 9.81m/s²
S=25m
U=?
Step three :
Substituting into the equation we have
0²=U²+2*9.81*25
0=U²+490.5
U²=-490.5
U=√490.5
U=22.14m/s
Answer:
He sees the ball coming at him at 150 km/hr.
Explanation:
In Newtonian physics, the observer would say that the velocity of the first object is the sum of the two velocities.
Due to the same direction, both velocities will be added.
Answer: 6,400 km
Explanation:
The weight of a person is given by:
where m is the mass of the person and g is the acceleration due to gravity. While the mass does not depend on the height above the surface, the value of g does, following the formula:
where
G is the gravitational constant
M is the Earth's mass
r is the distance of the person from the Earth's center
The problem says that the person weighs 800 N at the Earth's surface, so when r=R (Earth's radius):
(1)
Now we want to find the height h above the surface at which the weight of the man is 200 N:
(2)
If we divide eq.(1) by eq.(2), we get
By solving the equation, we find:
which has two solutions:
--> negative solution, we can ignore it
--> this is our solution
Since the Earth's radius is , the person should be at above Earth's surface.
Answer:
F = 36 N
Explanation:
Given that,
Charge, q₁ = +8 μC
Charge, q₂ = -5 μC
The distance between the charges, r = 10 cm = 0.1 m
We need to find the magnitude of the electrostatic force. The formula for the electrostatic force is given by :
So, the magnitude of the electrostatic force is 36 N.
Answer:
v= 1495.04 m/s
Explanation:
The formula for velocity of sound is given by ;
v= fλ --------where
v= velocity of sound
f= frequency of turning fork
λ = wavelength
However,
Δ L = 1/2 λ ------where Δ L is spacing between resonances.
1.46 = 1/2 λ
1.46 * 2 = λ
2.92 m = λ
v= fλ
v= 512 * 2.92
v= 1495.04 m/s