Answer:
Explanation:
Near point = 56 cm .
near point of healthy person = 25 cm
person suffers from long sightedness
convex lens will be required .
object distance u = 25 cm
image distance v = 56 cm
both will be negative as both are in front of the lens.
lens formula
I/v - 1 / u = 1/f
- 1/56 +1/25 = 1/f
- .01785 + .04 = 1/f
1/f = .02215
f = 45.15 cm .
Answer:
Death, Destruction, Loss of home
Speed = (frequency)x(wavelength).
Frequency = 6 Hz
Wavelength = 9mm = 0.009m.
Speed = (6 Hz) x (0.009m) = 0.054 m/s or 54 mm/sec.
Answer:

Explanation:
Given that
Speed ,v= 2 x 10⁵ m/s ( - y direction)
B= 0.6 T (- z direction)
The resultant force on the proton given as

F= m a
For uniform motion acceleration should be zero.
F = 0






Electric filed should be apply in the negative x direction.
Answer:
the initial speed of the arrow before joining the block is 89.85 m/s
Explanation:
Given;
mass of the arrow, m₁ = 49 g = 0.049 kg
mass of block, m₂ = 1.45 kg
height reached by the arrow and the block, h = 0.44 m
The gravitational potential energy of the block and arrow system;
P.E = mgh
P.E = (1.45 + 0.049) x 9.8 x 0.44
P.E = 6.464 J
The final velocity of the system after collision is calculated as;
K.E = ¹/₂mv²
6.464 = ¹/₂(1.45 + 0.049)v²
6.464 = 0.7495v²
v² = 6.464 / 0.7495
v² = 8.6244
v = √8.6244
v = 2.937 m/s
Apply principle of conservation of linear momentum to determine the initial speed of the arrow;

Therefore, the initial speed of the arrow before joining the block is 89.85 m/s