Question

Answer 1

Đổi: \(90\left(\dfrac{km}{h}\right)=25\left(\dfrac{m}{s}\right)-36\left(\dfrac{km}{h}\right)=10\left(\dfrac{m}{s}\right)\)

Gia tốc:

\(a=\dfrac{v^2-v_0^2}{2a}=\dfrac{10^2-25^2}{2\cdot50}=-5,25\left(\dfrac{m}{s^2}\right)\)

Thời gian:

\(t=\dfrac{v-v_0}{a}=\dfrac{10-25}{-5,25}=\dfrac{20}{7}s\)

Quãng đường:

\(s=\dfrac{v^2-v_0^2}{2a}=\dfrac{0^2-25^2}{2\cdot\left(-5,25\right)}\approx59,5m\)

Thời gian:

\(t=\dfrac{v-v_0}{a}=\dfrac{0-25}{-5,25}\approx4,76s\)