The answer is A. meters (m)
Answer:
location of battery in this diagram is at A and location of switch is at B.
Explanation:
First, we need to determine the distance traveled by the car in the first 30 minutes,
.
Notice that the unit measurement for speed, in this case, is km/hr. Thus, a unit conversion of from minutes into hours is required before proceeding with the calculation, as shown below

Now, it is known that the car traveled 40 km for the first 30 minutes. Hence, the remaining distance,
, in which the driver reduces the speed to 40km/hr is
.
Subsequently, we would also like to know the time taken for the car to reach its destination, denoted by
.
.
Finally, with all the required values at hand, the average speed of the car for the entire trip is calculated as the ratio of the change in distance over the change in time.

Therefore, the average speed of the car is 50 km/hr.
Answer:
A) Cold object will start getting hot
B) Heat exchange will stop as the two object acquire the same temperature.
Explanation:
A) When one hot object and one cold object are kept in contact then the heat is transferred from the hot object to the cold object via different modes of heat transmission. Hence, the cold object starts getting hot
B) The transmission of heat from the hot object to the cold object will stop as the temperature of the two object becomes equal to each other.
The force of gravity between two objects is given by:

where
G is the gravitational constant
m1 and m2 are the masses of the two objects
r is their separation
In this problem, the mass of the object is

, while the Earth's mass is

. Their separation is

, therefore the gravitational force exerted on the object is