Question

Тело массой 200г брошено с высоты 125 м чему будет равны потенциальная и кинетическая энергия тела через 1 и 5 с движения?в этом и следующим задачах принятьG равно 10м/с

Answer 1

H= h₀+(gt²/2)

Вычислим высоту через 1 с:
h= 125- (10*1²/2)= 120 м

Через 5 с:
h= 125-(10*5²/2)= 0 м (Тело упадет)
 
v= gt
v= 10*1= 10 м/с
v= 10*5= 50 м/с
Потенциальная энергия через 1 с:

E пот.= mgh
E пот.= 0,2*10*120= 240 Дж
Через 5 с: 0 Дж (Тело не обладает потенциальной энергией)

Кинетическая энергия через 1 с:
E кин.= mv²/2
E кин.= 0.2*100/2= 10 Дж

Через 5 с: 0,2* 2500/ 2= 250 Дж   .

Ответы выделены.

Answer 2

Calculation of Potential and Kinetic Energy

To calculate the potential and kinetic energy of an object, we need to use the formulas for each type of energy.

The potential energy (PE) of an object is given by the formula:

PE = mgh

where: - m is the mass of the object (200 g = 0.2 kg) - g is the acceleration due to gravity (10 m/s^2) - h is the height from which the object is dropped (125 m)

The kinetic energy (KE) of an object is given by the formula:

KE = (1/2)mv^2

where: - m is the mass of the object (0.2 kg) - v is the velocity of the object

Let's calculate the potential and kinetic energy of the object after 1 second and 5 seconds of motion.

Calculation after 1 second:

To calculate the potential energy after 1 second, we need to calculate the height from which the object has fallen. Since the object has been dropped, the height will decrease linearly with time. After 1 second, the height can be calculated using the formula:

h = h0 - (1/2)gt^2

where: - h0 is the initial height (125 m) - g is the acceleration due to gravity (10 m/s^2) - t is the time (1 s)

Substituting the values into the formula, we get:

h = 125 - (1/2)(10)(1)^2 = 125 - 5 = 120 m

Now we can calculate the potential energy using the formula:

PE = mgh = (0.2)(10)(120) = 24 J

To calculate the kinetic energy after 1 second, we need to calculate the velocity of the object. Since the object has been dropped, the velocity will increase linearly with time. After 1 second, the velocity can be calculated using the formula:

v = gt

Substituting the values into the formula, we get:

v = (10)(1) = 10 m/s

Now we can calculate the kinetic energy using the formula:

KE = (1/2)mv^2 = (1/2)(0.2)(10)^2 = 10 J

Therefore, after 1 second of motion, the potential energy of the object is 24 J and the kinetic energy is 10 J.

Calculation after 5 seconds:

To calculate the potential energy after 5 seconds, we can use the initial height of 125 m, as the object will have reached the ground by then. Therefore, the potential energy after 5 seconds is:

PE = mgh = (0.2)(10)(125) = 250 J

To calculate the kinetic energy after 5 seconds, we need to calculate the velocity of the object. Since the object has been dropped, the velocity will increase linearly with time. After 5 seconds, the velocity can be calculated using the formula:

v = gt

Substituting the values into the formula, we get:

v = (10)(5) = 50 m/s

Now we can calculate the kinetic energy using the formula:

KE = (1/2)mv^2 = (1/2)(0.2)(50)^2 = 250 J

Therefore, after 5 seconds of motion, the potential energy of the object is 250 J and the kinetic energy is 250 J.

Please note that the calculations assume no air resistance and a constant acceleration due to gravity.