College physics homework mathphys man i need ur hwlp

5.9 m/s²

78 N

Explanation:

Draw a free body diagram for each mass.

The mass on the left (M) has a tension force pulling up (T) and a weight force pulling down (Mg).

The mass on the right (m) has a tension force pulling up (T) and a weight force pulling down (mg).

Apply Newton's second law to the mass on the left (remember it accelerates down):

∑F = ma

T − Mg = M (-a)

T − Mg = -Ma

Apply Newton's second law to the mass on the right:

∑F = ma

T − mg = ma

Two equations, two unknowns (T and a).  First, we want to find a.  So start by subtracting the first equation from the second equation.

(T − mg) − (T − Mg) = ma − (-Ma)

T − mg − T + Mg = ma + Ma

Mg − mg = (m + M) a

a = g (M − m) / (m + M)

Given M = 20 kg and m = 5 kg:

a = 9.8 m/s² (20 kg − 5 kg) / (5 kg + 20 kg)

a = 5.88 m/s²

Now plug into either equation to find the tension.

T − mg = ma

T = mg + ma

T = m (g + a)

T = (5 kg) (9.8 m/s² + 5.88 m/s²)

T = 78.4 N

Rounding to two significant figures, the acceleration and tension are 5.9 m/s² and 78 N.

Notice that the radius of the pulley and the distance between the masses were extra information.

d. platinum would have the greatest temperature increase because it has the lowest specific heat.