Answer:Bohr placed the electrons in distinct energy levels. Rutherford described the atom as consisting of a tiny positive mass surrounded by a cloud of negative electrons. Bohr thought that electrons orbited the nucleus in quantised orbits.
Explanation: also rutherfords was just a hypothesis while Bhor took the time to make his an experiment
The acceleration of the race car after 12.0 seconds is -3.33 m/s^2.
To find the acceleration of the race car after 12.0 seconds, we need to use the formula for acceleration: acceleration = change in velocity / time. The initial velocity of the race car is 144 km/h, and it comes to a halt, so the final velocity is 0 km/h. We need to convert these velocities to meters per second (m/s) before using the formula.
Given that 1 km/h = 0.2778 m/s, the initial velocity is 144 km/h x 0.2778 m/s = 40 m/s. Similarly, the final velocity is 0 km/h x 0.2778 m/s = 0 m/s.
Plugging these values into the formula, we get: acceleration = (0 m/s - 40 m/s) / 12.0 s = -3.33 m/s^2.
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Answer:
Average speed of the car is 36.36 miles per hour
Explanation:
It is given that,
Total distance traveled by the car, d = 200 miles
Total time taken, t = 5.5 hours
In this case, we have to find the average speed of the car. Average speed of the car is defined as the total distance divided by total time taken. Mathematically, it can be written as :
s = 36.36 miles per hour
Hence, the average speed of the car is 36.36 miles per hour.
The mechanical advantage of the lever shown in the question is 1.27. Mechanical advantage is the force amplified by a mechanical tool. Thus, the correct option is B.
Mechanical advantage is the measure of the force amplification which is achieved by using a tool such as, a mechanical device or machine system. The mechanical device trades off input forces against the movement to obtain a desired amplification in the output force of the system.
Mechanical advantage of the lever is simply the ratio of the effort arm to the load arm. Effort arm is the distance from the pivot to the point of application of the force while the load arm is the distance of the lord from the pivot point.
Therefore, the effort arm is 0.27m while the load arm is 0.2 m. Mechanical advantage is calculated through the formula:
MA=effort arm/load arm
MA = 0.27/0.2
MA = 1.35 which is close to 1.27
Therefore, the correct option is B.
Learn more about Mechanical advantage here:
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Your question is incomplete, most probably the complete question is:
What is the mechanical advantage of the level shown below?
A. 0.79
B. 1.27
C. 2.6
D. 3.67
Answer:1.35
Explanation: