Answer:
18.5 m/s
Explanation:
On a horizontal curve, the frictional force provides the centripetal force that keeps the car in circular motion:

where
is the coefficient of static friction between the tires and the road
m is the mass of the car
g is the gravitational acceleration
v is the speed of the car
r is the radius of the curve
Re-arranging the equation,

And by substituting the data of the problem, we find the speed at which the car begins to skid:

Answer:B,C,D
Explanation:
Thermodynamic efficiency is given by

efficiency can be increased by Keeping
constant and increasing 
Keeping
constant and decreasing
by increasing 
by decreasing
ratio
W=MG
w is weight
m is mass
g is gravity
W=(100 kg)(9.8 m/s)
W= 980 N
hope this helps
Answer:
i). Inverted
ii). Magnification of the image = -0.5
iii). Real
Explanation:
As shown in the ray diagram attached,
An object AB has been placed in front of converging lens (convex lens) at u = 30 cm.
F (Focus) of the lens is at 10 cm. So F = 10 cm
By analyzing the ray diagram we can measure the distance of the image on the other side of the lens (By counting the small blocks of the graph)
V = 15 cm
Characteristics of the image is:
i) Inverted
ii) Magnification of the image = 
= -0.5
ii) Real