Their relative speed is the sum of 60 and 40 or 100km/hr. They will travel the 150km in 1.5 hrs. When two object approach each other, the closing speed is just the sum of the speeds, therefore, the closing speed is your case is 100kph. So they will meet in 1.5 hours.
Answer:
v = 1.6 m/s
Explanation:
Given that,
Distance, d = 72 m
Time taken, t = 45 s
We need to find their average velocity. Average velocity of an object is given by total distance divided by total time taken.

So, their average velocity is 1.6 m/s.
Answer:
mass and volume
Explanation:
matter is anything that has mass and occupies space(volume)
Answer:
Time = 6 years
Explanation:
First, we will calculate the no. of half life periods required to reduce the mass of Protactinium to the given value:

where,
n = no. of half-life periods = ?
m = initial mass = 86.3 g
m' = remaining mass = 10.8 g
Therefore,

Since the bases are the same. Therefore equating powers:
n = 3
Now we calculate the time:

<u>Time = 6 years</u>
Answer:
1.25 focal lengths
Explanation:
The lens equation states that:

where
f is the focal length
p is the object distance
q is the image distance
In this problem, the image is 4 times as far from the lens as is the object: this means that

If we substitute this into the lens equation and we rearrange it, we get

so, the object distance measured in focal lengths is
1.25 focal lenghts