Question

Force is applied on an object of mass 2 kg at rest on a frictionless horizontal surface as shown in the graph. The speed of object at t = 1 s will be F(N) 20 F 10+ t(s) 5 10 (1) 7.5 m/s (2) 12.5 m/s (3) 10 m/s (4) 25 m/s


pls tell the explanation too​

Answer 1

Answer:

Correct option is  A  7.5

Explanation:

As we know that Force F=  dP/dt   , P is momentum so dP=Fdt where dP is change in momentum due to force F

In other words the momentum imparted by force will be given by the area under the F−t graph  

so ΔP=area=smaller rectangle + larger vertical rectangle =10N×(0.5−0)s+20N×(1.0−0.5)s

or ΔP=15Ns

so the velocity change is Δv=  15Ns/mass   =7.5m/s

as the mass started from mass so new velocity will be 7.5m/s