Answer:
C. 900J (i tried my best)
Explanation:
the student's mass=60kg
gravitational field strength= 10N/kg:
1kg = 10N
60kg = 600N
(where 600N is the gravitational field strength of the student)
√1.5²+2² (pythagoras theorem)
=2.5m (the stairs' length)
work done= N x distance move in the direction of force (m)
=600N x 2.5m
=1500J @ Nm
1500J - 600N (gravitational field strength of the student)
=900J(??)
-correct me if i'm wrong i'm just a human :)
Answer:
Explanation:
Equation for translational kinetic energy = 1/2 m V² where m is mass and V is velocity .
In first case let mass of car be m
Translational kinetic energy = 1/2 m x 40² = 800 m .
In the second case ,
Translational kinetic energy = 1/2 m x 20² = 200 m
So , in former case kinetic energy of car is 4 times that of second case.
Answer:
E = h f and since f = c / λ we have E = h c / λ
Thus λ = h c / E
Also, 1 ev = 1.6E-19 C
λ = 6.63E-34 * 3.0E8 / (1.6 * 1.6E-19)
λ = 6.63 * 3.0 / (1.6 * 1.6) * E-7
λ = 7.77E-7 = 777 nanometers
(B) is correct
Answer:
x₁ = 0.1878 m
Explanation:
For this exercise we will use conservation of energy
starting point. Highest point
Em₀ = U = m g h
final point. Lowest point with fully compressed spring
Em_f = K_e + U
Em_f = ½ K x² + m g x
energy is conserved
Em₀ = Em_f
m g h = ½ K x² + m g x
½ K x² + mg (x- h) = 0
let's substitute
½ 7.3 x² + 0.030 9.8 (x- 0.25) = 0
3.65 x² + 0.294 (x- 0.25) = 0
x² + 0.080548 (x- 0.25) = 0
x² - 0.020137 + 0.080548 x = 0
x² + 0.080548 x - 0.020137 = 0
let's solve the quadratic equation
x = [0.080548 ±√ (0.080548² + 4 0.020137)] / 2
x = [0.080548 ± 0.29502] / 2
x₁ = 0.1878 m
x₂ = -0.1072 m
These are the compression and extension displacement of the spring
