Answer:

Explanation:
given,
refractive index of lens, n = 1.70
Radius of curvature of front surface. R₁ = 20 cm
Radius of curvature of the back surface, R₂ = 30 cm
focal length= ?

R₁ = +20 cm
R₂ = -30 cm
n = 1.70




the focal length of the lens is equal to 17.15 cm
Answer:
c. They hit at the same time
b. BGS
Explanation:
A marble dropped (initial vertical velocity is 0) will land at the same time as a marble launched horizontally (initial vertical velocity is 0) from the same height.
Boat S has a net speed of 5 m/s (10 − 5).
Boat B has a net speed of 15 m/s (10 + 5).
Boat G has a net speed of ≈11.2 m/s (√(10² + 5²)).
Answer:
c
Explanation:
Friction is caused by how rough and object is, and how much the object weighs, as this causes it to drag more.
Answer:
A book on its side exerts a greater force.
Explanation:
Pressure = Force / Area
Assuming that 1kg = 10N
2kg = 20N
Area of book lying flat = 0.3m × 0.2m
= 0.6m²
Pressure of book lying flat = 20N / 0.6m²
= 30Pa (1 s.f.)
Area of book on its side = 0.2m × 0.05m
= 0.01m²
Pressure of book on its side = 20N / 0.01m²
= 2000Pa (1 s.f.)
Since 2000Pa (1 s.f.) > 30Pa (1 s.f.), a book on its side applies greater pressure than lying flat.
Answer:
5773.50269 Hz
23 A
Explanation:
= Inductance = 6 mH
= Capacitance = 5 μF
= Resistance = 3 Ω
= Maximum emf = 69 V
Resonant angular frequency is given by

The resonant angular frequency is 5773.50269 Hz
Current is given by

The current amplitude at the resonant angular frequency is 23 A