Dear ,Huong

I'm delighted that you're enjoying the healthy cooking book! Sunday sounds fantastic - I'll definitely be there. Could you please let me know what time you'd like me to arrive? I'll be sure to bring along some fresh mangoes from my garden. Is there anything else you need me to bring? Can't wait to cook together!

Warm regards,

Trang

Chọn mốc thế năng ở mặt đất

Ta có: W=Wđ +Wt<=> W=2,5Wt= 2,5.m.g.z

           Wđ= 1,5.Wt <=> W=2,5Wt= 2,5.m.g.z

<=> m= W/ 2,5.g.z= 37,5/2,5.10.3=0,5 (kg)

Tương tự: W=5/3Wđ=5/3.1/2.m.v^2

Vận tốc là: v0= 

=+-căn W/5/6m = +-3 căn 10( m/s)

Đổi: 21,6km/h= 6m/s

m=2 tấn= 2000kg

Ta có: Vt= Vo+at

=> a=(Vt-Vo)/t =(6-0)/15 = 0,4m/s^2

Qũng đường xe đi được là :

S= (Vt^2 -Vo^2) / 2a = ( 6^2  -0^2 ) / 2.0.4=45m

a, Ta có : F= ma= 2000.0,4=800N

A=F.S=800.45=36000J

P=A/t= 36000/15= 240W

b, Ta có : Fms= 0,005.N= 0,005.2000.10=1000N

Ap dụng định luật II Newton: F-Fms=ma

=> F=Fms+ma= 1000+2000.0,4=1800N

A= F.S=1800.45=81000J

P=A/t = 81000/15= 5400W