Q: A mass M is initially at rest on a horizontal surface, s =0.30 and k =0.20 .

Question

Q: A mass M is initially at rest on a horizontal surface,s=0.30 andk=0.20 . A horizontal string then pulls Mwith a tension T. Forces below are magnitudes. Indicate if thestatement is correct or incorrect and WHY:
1. T equals sN if M remains atrest
2. The NET force on M (if M does not move) is T
3. If M does not accelerate, then T sN
4. N equals Mg
5. M will accelerate if T exceedskN
6. M will accelerate if T exceedsN

Explanation / Answer

g=acceleration due to gravity N=M*g so statement 4 is correct maximum static frictional fore=s*N so when T=s*N M is set on the verge of motion. sostatement 1 is incorrect when M does not move net force on M =0 so statement 2 isincorrect the minimum force required to set the mass M into motion iss*N only if T >s*N M will beset into motion once M is in motion kinetic friction acts and Tmust be greater than k*N to have anyacceleration maximum kinetic frictional force=k*N so if M hasto accelerate T must be greater than k*N once M isalready in motion .so M will accelerate if T exceedsk*N but statement 5 is incorrect since it does notstate if M is already in motion and to set M into motion forcerequired=s*N since s*N is greater than k*N Mwill accelerate when T exceeds s*N so statement 6is correct

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.