The car heads east at an average speed of 50 miles per hour from the intersection point towards East. The truck heads east at an average speed of 60 miles per hour from the intersection point towards South.
The distance of car from the intersection point after t hours is
.
The distance of truck from the intersection point after t hours is
.
Since these distances are perpendicular to each other, distance apart d (in miles) at the end of t hours is

Thus the distance apart is 
Answer: b
Explanation:
When heat is released by the system i.e. system loses heat. So, we take it as negative -Q
When the work is done on the system then it is considered as negative work on the system i.e. -W
In this case, the plunger is pulled out, and work is done on the system. So, we take work as negative work -W
Correct option is b
Seven days after a waxing gibbous moon, the moon will be waning gibbous, and at some point during that seven days, it will have been Full.
Answer:
1. a) 72 N.
2. a) 2 m/s².
Explanation:
Given the following data;
1. Mass = 90kg
Acceleration = 0.8 m/s²
To find the force;
Force = mass * acceleration
Force = 90 * 0.8
Force = 72 Newton.
2. Mass = 50kg
Force = 100N
To find the magnitude of acceleration;
Acceleration = force/mass
Acceleration = 100/50
Acceleration = 2 m/s²