Question

A 114.8 g ball of blue putty is travelling East (to the right) with a velocity of 1.39 m/s. A second ball of red putty (74.4 g) is travelling North of West at 31.1 degrees with a velocity of 3.04 m/s. The two balls of putty collide and form 1 single blue/red putty blob.

The new combined blob hits a wall perpendicular to the direction of travel and sticks to it with a collision lasting 0.0023 seconds.

What magnitude force did the wall exert on the blob to stop it?

Your answer should have 1 digits past the decimal.

Answer 1

here,

mass of blue putty ,m1 = 0.1148 kg

mass of red Putty , m2 = 0.0744 kg

initial speed of blue putty , u1 = 1.39 m/s

initial speed of red putty , u2 = 3.04 m/s

let the final speed after the collison be v

using conservation of momentum

m1 * u1 + m2 * u2 = (m1 + m2) * v

0.1148 * 1.39 i + 0.0744 * 3.04 * ( - cos(31.1) i + sin(31.1) j) = ( 0.1148 + 0.0744) * v

solving for v

v = - 0.18 m/s i + 0.62 m/s

time taken , t = 0.0023 s

the magnitude of net force , F = impulse /time taken

F = m * sqrt(0.18^2 + 0.62^2)/0.0023 N

F = (0.1148 + 0.0744) * sqrt(0.03^2 + 1.25^2)/0.0031 N

F = 53.1 N