Question

Proszę o wykonanie tych zadań :)

Answer 1

1.

dane:

F = 200 N

s = 4 m

szukane:

W = ?

 

W = F x s = 200N x 4m

W = 800J

========

2.

dane:

h = 50 cm = 0,5 m

g = 10 m/s2 = 10 N/kg

szukane:

dEp = ?

 

dEp = m x g x h = 7kg x 10N/kg x 0,5m

dEp = 35J(dżuli)

===============

3.

dane:

m = 900 kg

v = 10 m/s

szukane:

W = ?

 

Ek =W

Ek = mv^2/2

W = 900kg x(10m/2)^2/2 = 45 000 J

W = 45 kJ (kilodżuli)

==================

4.

dane:

h = 2 m

W = 100 J

g = 10 N/kg

szukane:

m = ?

a) Ek(2m) = ?

b) Ek(1m) = ?

 

Ep = W

Ep = mgh

mgh = W  I:gh

m = W/gh = 100J/(10N/kg x 2m)

m = 5kg

========

a)

mgh = mv^2/2

gh = v^2/2  I*2

v^2 = 2gh

v = V(2gh)

 

v = V(2 x 10m/s2 x 2m) = 2V10 m/s

Ek = mv^2/2 = 5kg x(2V10m/s)/2

Ek = 100 J

=========

b)

v = V2gh = V(2 x 10m/s2 x 1m)

Ek = mv^2/2 = 5kg x(2V5m/s)^2/2

Ek = 50 J

========

5.

dane:

v = 10 m/s

g = 10 m/s2

szukane:

h = ?

 

Z zasady zachowania energii mechanicznej:

Ep = Ek

mgh = mv^2/2  /:m

gh = v^2/2  I*2

2gh = v^2  /:2g

h = v^2/2g = (10m/s)^2/(2 x 10m/s2)

h = 0,5m

========

6.

dane:

P = 30 W

t1 = 40s

t2 = 1/2 h = 1800s

szukane:

W1 = ?

W2 = ?

 

P = W/t  I*t

W = P x t

W1 = 30W x 40s = 1 200J = 1,2 kJ

W2 = 30W x 1800s = 54 000JU = 54kJ

7.

dane;

W = 800 J

t = 20s

szukane;

P = ?

 

P = W/t = 800J/20s

P = 40 W (watów)

================

 

Pozdrawiam ;)