The statement is false. Vectors are used to solve projectile motion problems because they allow the analysis of one direction at a time for two-dimensional motion. Scalar quantities can be used to analyze linear motion problem, but not projectile motion.
Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length

Put the value into the formula



When , R₁= -4, R₂ = 8
Put the value into the formula



When , R₁= 4, R₂ = -8
Put the value into the formula



When , R₁= -4, R₂ = -8
Put the value into the formula



Hence, The lenses with different focal length are four.
Answer:

Explanation:
As we know that magnitude of two vectors is given as

here we know that
A = magnitude of vector A
B = magnitude of vector B
= angle between two vectors
so here we know that
A = 30 units
B = 40 units
angle = 90 degree
so we have



Answer:
The two forces acting on the object are weight due to gravity pulling the object towards earth, and drag resisting this motion. When the object is first released, drag is small as velocity is low, so the resultant force is down. This means the object accelerates towards earth.