Answer:
e) 120m/s
Explanation:
When the ball reaches its highest point, its velocity becomes zero, meaning
.
where 
is the initial velocity.
Solving for 
we get
which is the time it takes the ball to reach the highest point.
Now, after the ball has reached its highest point, it turns around and falls downwards. After time 
since it had reached the highest point, the ball has traveled downwards and the velocity 
it has gained is
,
and we are told that this is twice the initial velocity ; therefore,
which gives
Thus, the total time taken to reach velocity 
is
This 
, we are told, is 36 seconds; therefore,
and solving for we get:
which from the options given is choice e.
A. Diagram A
B. Diagram C & D
C. Diagram B
D. Diagram C & D
E. Diagram B
F. Diagram C & D
These are simplified representations of an object's body and the force vectors acting on it. Some of the main forces that are involve are normal force, friction, push or pull and gravity.
Answer:
The work function ϕ of the metal = 53.4196 x 10⁻¹⁶ J
Explanation:
When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.
The relationship between the maximum kinetic energy (
) of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:
= h(f − f₀)
= hf - hf₀
E is the energy of the absorbed photons: E = hf
ϕ is the work function of the surface: ϕ = hf₀
= E - ϕ
Frequency f = 8.12×10¹⁸ Hz
Maximum kinetic energy = 4.16×10⁻¹⁷ J
Speed of light c = 3 x 10⁸ m/s
Planck's constant h = 6.63 × 10⁻³⁴ Js
E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸
E = 53.8356 x 10⁻¹⁶ J
from = E - ϕ ;
ϕ = E -
ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷
ϕ = 53.4196 x 10⁻¹⁶ J
The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J
Answer:
11.95m/s
Explanation:
A moving object has a kinetic energy of 150 J and a momentum of 25.1 kg·m/s.
a) Find the speed of the object. Answer in units of m
K. E =½mv²
150= ½mv²
Multiply both sides by 2
mv² = 300
Divide both sides by v²
m = 300/v² .................. Equation 1
Momentum is the product of mass and velocity
Momentum = mv
25.1 = mv
Divide both sides by v
m = 25.1/v ................ Equation 2
Equate equations 1 and 2
300/v² = 25.1/v
Cross multiply
25.1v² = 300v
Multiply v with both sides
25.1v = 300
Divide both sides by 25.1
v = 300/25.1
V = 11.95m/s
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