Answer:
1.5 km/s²
Explanation:
Given that:
a car starts from rest; it means the initial velocity (u) = 0 km/hr = 0 m/s
after time (t) = 20 seconds
the final velocity = 108 km/hr = 30 m/s
The acceleration (a) of the car can be determined by using the formula:



a = 1.5 km/s²
A concave mirror is an example of curved mirrors. So that the appropriate answer to the given question is option D. The rays will cross at the focal point.
A concave mirror is a type of mirror in which its inner part is the reflecting surface, while its outer part is the back of the mirror. This mirror reflects all parallel rays close to the principal axis to a point of convergence. It can also be referred to as the converging mirror.
In this type of mirror, all rays of light parallel to the principal axis of the mirror after reflection will cross at the focal point.
Therefore, the required answer to the given question is option D. i.e The rays will cross at the focal point.
For reference: brainly.com/question/20380620
Explanation:
Let
is the mass of proton. It is moving in a circular path perpendicular to a magnetic field of magnitude B.
The magnetic force is balanced by the centripetal force acting on the proton as :

r is the radius of path,

Time period is given by :


Frequency of proton is given by :

The wavelength of radiation is given by :


So, the wavelength of radiation produced by a proton is
. Hence, this is the required solution.
Fnet = (mass) (acceleration)
= 11 kg x 3.7m/s^2
= 41 N
Using the principle of floatation.
u = w............(a)
Upthrust of fluid is equal to the weight of the object.
Let the volume of the wood be V.
The upthrust u, is related to the volume submerged in water, and that is 1/5 of it volume, that is (1/5)V = 0.2V
Formula for upthrust, u = vdg
where v = volume of fluid displaced
d = density of fluid
g = acceleration due to gravity
weight, w = mg
where m = mass
g = acceleration due to gravity
From (a)
u = w
vdg = mg Cancel out g
vd = m
The v is equal to 0.2V, which is the submerged volume. Notice that the small letter v is volume of fluid displaced, and capital V is the volume of the solid.
d is density of fluid which is water in this case, 1000 kg/m³
0.2V * 1000 = m
200V = m
Hence the mass of the object is 200V kg.
But Density of solid = Mass of solid / Volume of solid
= 200V / V
= 200 kg/m³
Density of solid = 200 kg/m³