A car drives up a straight hill at a constant
speed of 60 kilometers per hour. A truck
drives over the crest of the hill at a constant
speed of 60 miles per hour.
What is the net force on the car and on the
truck?
1. both not zero
2. not zero; zero
3. both zero
4. zero; not zero
No. The answer is 4.
A net centripetal force is needed to allow the car to go over the crest of the hill at constant speed.
Well, it seems like the car and the truck are having a little race up the hill! But let's talk about the forces involved.
For the car, since it's driving up the hill at a constant speed, we know that the net force on it must be zero. This means that the force pushing the car up the hill is equal to the force pulling it down, resulting in no net force.
Now let's take a look at the truck. It is also driving over the crest of the hill at a constant speed. However, since the speed is given in miles per hour, and the car's speed is given in kilometers per hour, we need to do a little conversion first.
So, let's convert the truck's speed of 60 miles per hour to kilometers per hour. 1 mile is approximately equal to 1.60934 kilometers, so 60 miles would be around 96.5604 kilometers. Therefore, the truck is moving at roughly 96.5604 kilometers per hour.
Now, just like the car, since the truck is moving at a constant speed, the net force on it must also be zero.
So, the correct answer is option 3: both the net force on the car and the net force on the truck are zero.
Looks like they're both feeling pretty balanced on their way up the hill!
The net force is defined as the sum of all forces acting on an object. In this case, the car and the truck are both driving at a constant speed.
The car is driving up a straight hill at a constant speed of 60 kilometers per hour, which means it is experiencing a gravitational force pulling it downwards and a force from the engine pushing it upwards. These two forces are equal in magnitude and opposite in direction, resulting in a net force of zero on the car.
On the other hand, the truck is driving over the crest of the hill at a constant speed of 60 miles per hour. Since it is also experiencing a gravitational force pulling it downwards and a force from the engine pushing it upwards, the net force on the truck is also zero.
Therefore, the correct answer is option 3: both forces are zero.
To determine the net force on the car and the truck, we need to understand the relationship between velocity, mass, and acceleration. The net force can be calculated using Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration.
In this scenario, both the car and the truck are moving at a constant speed. Since they maintain a constant velocity, their acceleration is zero. According to Newton's second law, if acceleration is zero, the net force is also zero.
Therefore, the correct answer is option 3: both the net force on the car and the net force on the truck are zero.