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 : The final volume of the balloon at this temperature and pressure is, 17582.4 L
Solution :
Using combined gas equation is,
where,
= initial pressure of gas = 1 atm
= final pressure of gas = 0.3 atm
= initial volume of gas = 6000 L
= final volume of gas = ?
= initial temperature of gas = 273 K
= final temperature of gas = 240 K
Now put all the given values in the above equation, we get the final pressure of gas.
Therefore, the final volume of the balloon at this temperature and pressure is, 17582.4 L
Answer:
The ball thrown downward
Explanation:
When the ball is thrown vertically, the acceleration of it is the gravity acceleration independent if it is thrown downward or upward. However, the acceleration is a vector, so, when the ball is thrown upward, the movement is against the gravity, so the acceleration is negative, and so, the velocity decreases during time; and when the ball is thrown downward, the movement goes to the gravity, so the acceleration is positive, so the velocity increase after time passes.
Answer:
Explanation:
Magnitude of frictional force = μ mg
μ is either static or kinetic friction.
To start the crate moving , static friction is calculated .
a ) To start crate moving , force required = μ mg where μ is coefficient of static friction .
force required =.517 x 56.6 x 9.8 = 286.76 N .
b ) to slide the crate across the dock at a constant speed , force required
= μ mg where μ is coefficient of kinetic friction , where μ is kinetic friction
= .26 x 56.6 x 9.8 = 144.21 N .
