Answer:
a) a = 0
b) W = 29.72 N
Explanation:
a)The acceleration of an object is defined as the change of its speed with respect to a time interval, Because the briefcase remains at rest, its acceleration (a) is zero.
a=0
b) Calculation of the weight of the briefcase
The formula to calculate the weight is the following:
W= m*g Formula (1)
Where:
W : is the weight in Newtons (N)
m : is the mass in kilograms (kg)
g : is the acceleration due to gravity in meters over second square (m/s²)
Data
m=3.03 kg : mass of the briefcase
m=9.81 m/s² : acceleration due to gravity
We replace data in the formula (1)
W= m*g = 3.03 kg * 9.81 m/s²
W= 29.72 N
Answer: 50J
Explanation:
Mechanical energy follows the same principles of kinetic energy and potential energy, it is conserved. So Ei = Ef.
Mechanical energy is the sum of ALL energy's. There is no friction, so its just kinetic plus potential.
37.5 + 12.5 = 50J
Since the particle has not touched the ground, it has not transferred any energy to the ground yet, therefore the mechanical energy must still be 50J; mostly in kinetic energy with a very small amount of potential because of the low height relative to the ground.
The question is incomplete, the complete question is;
A student is measuring the volumes of nectar produced by a flowering plant for an experiment. He measures nectar from 50 flowers using a graduated cylinder that measures to the nearest millilitre (mL). Which statement describes a change that can help improve the results of his experiment?
A.) His measurements will be more precise if he takes measurements from an additional 100 flowers. B.) His measurements will be more accurate if he uses a graduated cylinder that measures to the nearest tenth of a mL. C.) His measurements will be more precise if he uses a graduated cylinder that measures to the nearest tenth of a mL. D.) His measurements will be more accurate if he takes measurements from an additional 100 flowers.
Answer:
His measurements will be more accurate if he uses a graduated cylinder that measures to the nearest tenth of a mL.
Explanation:
In the measurements of volume using most graduated cylinders, the cylinders are calibrated to the nearest tenth owing to the uncertainty in the measurement of volume.
Hence if a cylinder has measures to the nearest milliliter(mL), then he can improve his experiment by using a graduated cylinder that measures to the nearest tenth of a mL
Answer:
t = 6 [s]
Explanation:
In order to solve this problem we must first use this equation of kinematics.
where:
Vf = final velocity = 0 (the car comes to rest)
Vo = initial velocity = 72 [km/h]
a = acceleration [m/s²]
x = distance = 60 [m]
First we must convert the velocity from kilometers per hour to meters per second.
![72 [\frac{km}{h}]*\frac{1000m}{1km} *\frac{1h}{3600s} =20 [m/s]](https://tex.z-dn.net/?f=72%20%5B%5Cfrac%7Bkm%7D%7Bh%7D%5D%2A%5Cfrac%7B1000m%7D%7B1km%7D%20%2A%5Cfrac%7B1h%7D%7B3600s%7D%20%3D20%20%5Bm%2Fs%5D)
![0=(20)^{2} -2*a*60\\400 = 120*a\\a=3.33[m/s^{2} ]](https://tex.z-dn.net/?f=0%3D%2820%29%5E%7B2%7D%20-2%2Aa%2A60%5C%5C400%20%3D%20120%2Aa%5C%5Ca%3D3.33%5Bm%2Fs%5E%7B2%7D%20%5D)
Now using this other equation of kinematics.
0 = 20-3.33*t
t = 6[s]
The relative velocity of the athlete relative to the ground is 5.2 m/s
The given parameters;
constant velocity of the athlete, V = 5.2 m/s
let the velocity of the ground = Vg = 0
The relative velocity concept helps us to determine the velocity of a moving object relative to a stationary observer.
The athlete is the moving object in this question while the ground is stationary.
The relative velocity of the athlete relative to the ground is calculated as follows;
Thus, the relative velocity of the athlete relative to the ground is 5.2 m/s
Learn more here: brainly.com/question/24430414
