Answer:
18.5 cm
Explanation:
From;
1/u + 1/v = 1/f
Where;
u= object distance = 86cm
image height = 23 cm
Radius of curvature = 37 cm
The radius of curvature (r) is the radius of the sphere of which the mirror forms a part.
Focal length (f) = radius of curvature (r)/2 = 37cm/2 = 18.5 cm
Therefore, the focal length of the mirror is 18.5 cm
Answer:
sure if its easy im jp ill help u
Explanation:
Answer:
B.The force of friction between the block and surface will decrease.
Explanation:
The force of friction is given by
![F_s = \mu N](https://tex.z-dn.net/?f=F_s%20%3D%20%5Cmu%20N)
where
is the coefficient of friction and
is the normal force.
When the student pulls on the block with force
at an angle
, the normal force on the block becomes
![N = Mg- F_psin(\theta)](https://tex.z-dn.net/?f=N%20%20%3D%20Mg-%20F_psin%28%5Ctheta%29)
and hence the frictional force becomes
.
Now, as we increase
,
increases which as a result decreases the normal force
, which also means the frictional force decreases; Hence choice B stands true.
<em>P.S: Choice D is tempting but incorrect since the weight </em>
<em> is independent of the external forces on the block. </em>
Speed = distance/time
Speed of car = 125 km/2 hours
Car speed = 62.5 km/hr.